所谓犯罪门槛降低，即对成立犯罪所要求的严重程度有所降低，其表现为对罪量要素的要求有所降低，包括调整既有犯罪构成要件中的罪量要素，以及将部分原属治安违法或者行政违法的行为升格为犯罪。犯罪范围的扩张包括横向扩张和纵向延伸两种类型。其中，犯罪范围的横向扩张，是将之前存在规制疏漏的同类违法行为或者新出现的一些达到一定严重程度的行为予以犯罪化，犯罪范围的纵向延伸即表现为犯罪门槛降低。由此可见，犯罪门槛降低属于犯罪范围扩张的类型之一。 近年来，我国的刑事立法和刑事司法呈现出犯罪门槛降低的现象。我国犯罪门槛的降低具有正当性根据。第一，在当前多重社会转型的大背景下，随着“熟人社会”向“陌生人社会”转变，以传统非刑罚手段已难以遏制日趋严重的社会公共领域的失范现象，有必要降低犯罪的门槛，以加强对社会的治理，确立社会公共领域的基本规则。刑法作为社会治理的重要一环，应当随着社会的发展而不断变化。通过刑法参与社会治理，并非刑法工具主义的体现。第二，劳动教养制度废止之后，为了适应受原劳动教养处理的行为分流处理的必然要求，需要将部分受原劳动教养处理的行为纳入犯罪圈内。第三，犯罪门槛的降低，如知识产权犯罪门槛的降低，有效地缓解了外部国家的压力。第四，“严而不厉”的刑法结构应为我国刑法的理性选择，而随着预防刑法的出现、积极刑法立法观的确立，我国刑法已进一步呈现出“严而不厉”刑法结构的立法走向，犯罪门槛的降低符合这一立法走向。第五，在犯罪治理理念革新的背景下，国家“专治”领域应适当倡导刑事司法模式，这也就要求通过宽严相济刑事政策的刑法化，回应犯罪治理的要求。第六，刑法谦抑性理论的前提应当是犯罪圈已经相对较大，但仍然进一步扩大犯罪圈，而从这一前提来看，我国当前还不具备对包括犯罪门槛降低在内的犯罪范围扩张，一律以违反刑法谦抑性为由进行反对的空间。刑法谦抑性真正所强调的应是刑法有所为有所不为，仅仅强调刑法有所不为，不是刑法的谦抑性，而是刑法的惰性。刑法谦抑性要求刑法的处罚范围越合理越好，而非越窄越好，该入罪的行为一定要入罪。 我国刑法应当适当降低犯罪门槛，但不应当突破“立法定性+立法定量”的犯罪成立模式。司法权与行政权相比具有相对优势，但取消所有犯罪的犯罪门槛，势必造成犯罪案件大量增加，而不得不通过程序分流的方式将原警察机关所行使的权力转移至检察机关。检察机关一旦通过刑事司法程序恣意行使权力，所造成的负面后果可能更甚于行政机关的制裁。即使将案件交由法院审理，从司法者实际面对大量案件时的选择来看，司法权所被赋予的公平、正义期待可能也会大打折扣。采取犯罪成立立法定性模式的国家，面对大量轻微刑事案件，也不得不通过微罪处分制度、交通违章通告制度等行政制度予以转处。我国“法不治众”的法文化不应被完全抛弃，对待传统应当是一个扬弃的过程。我国建国以来的法治建设经验和现阶段的治理需要也要求应当适当降低犯罪门槛。犯罪门槛降低的过程中，对于轻微犯罪，仍应对其作出一定量上的限制，并针对情节较轻的行为辅之以行政处罚或者治安处罚，保持行政处罚与刑事处罚的二元制裁体系。 我国应当从宪法制约和民意回应两个方面对犯罪门槛的降低作出合理限制。由于犯罪门槛降低所针对的行为本身具有一定法益侵害性，因此，在降低犯罪门槛的过程中，并不需要借用符合宪法关联的法益侵害这一标准进行合宪性调控。是否应当降低犯罪门槛，主要应根据比例原则中的必要性原则和相当性原则进行判断，而不需要再根据适当性原则进行判断。就必要性原则而言，需要立法者判断适用刑罚是否属于针对该行为类型的损害最小的手段。就相当性原则而言，需要立法者判断对某一行为进行刑罚处罚之时，以刑罚保护某种法益，是否会造成对其他法益的侵害以及造成了何种程度的侵害。非理性民意影响刑法立法已呈现出世界性趋势。我国应当坚持对非理性民意的理性回应，形成理性面对民意的立法理念，重视增强立法的实证基础，并进一步完善立法程序问题。

The downward trend of the criminal threshold means that the requirements for the establishment of crime has been reduced, including two different situations, adjusting the amount or circumstance element of a crime and criminalizing administrative malfeasances. The horizontal expansion and the vertical expansion are two different types of expansions of the scope of crime. In the case of the horizontal expansion of the scope of crime, it criminalize some illegal acts that were unregulated or some new illegal acts that reach some certain extent. Then the vertical expansions take the form of the downward trend of the criminal threshold. In a word, the downward trend of the criminal threshold is a type of expansion of the scope of crime. There exists the downward trend of the criminal threshold in the criminal legislation and criminal justice in China recent years. The downward trend of the criminal threshold has been justified under the rule of law. Firstly, the transition from acquaintances society to strangers society is accompanied by the dimensions of transitional China. It is necessary to lower the criminal threshold to define the basic rules in the public fields and strengthen social governance because the emerging anomie phenomenon is becoming more and more severe and running out of control by using the non-criminal penalty. As an essential and fundamental part of social governance, criminal law is supposed to be of revision and perfection continuously with the transformation of the society. However, it is hardly to concede that the participation of social governance through criminal law is some sort of criminal legal instrumentalism. Secondly, after the abolition of the system of education through labor, parts of acts that were regulated by the education through labor should be brought into the scope of crime to adapt the inevitable requirement of disposing the acts separately under the system. Thirdly, the downward trend of the criminal threshold in the field of the intellectual property crime helps to ease the external pressure. Fourthly, as the postitive view of criminal legislation appeared and the prevention of criminal law emerged, the structure of China’s criminal law presents a legislative trend of ‘comprehensive but not severe’, which conforms to the downward trend of the criminal threshold. Fifthly, the pattern of criminal justice should be promoted in the field of national ‘special administration’ appropriately in the background of reforming the concept of crime governance. Thus, it requires the criminalization of the criminal policy of tempering justice with mercy to respond the requests of crime governance. Sixthly, the theory of the modesty principle demands further expansion of the scope of crime. On the premiss of this view of the scope of crime, there is no potential room to oppose the expansions of the scope of crime including the downward trend of the criminal threshold in the name of the modesty principle of criminal law in China. Because the modesty principle is supposed to emphasize that the criminal law should be ‘getting some things done while leaving others undone’. On the demand of the modesty principle, the scope of crime should be defined feasibly and reasonably to ensure that every criminal could be penalized for his illegal act. The legislative quantitative model of crime establishment in China’s criminal law should be retained. Compared with administrative power, judicial power has some relatively advantages. However, the criminal threshold cannot be removed, otherwise it would lead to a large increase in criminal cases and part of police power would be transferred to the procuratorate organs through procedure division. Once the procuratorial organs have deliberately exercised their power through criminal justice procedures, the negative consequences may be even greater than those imposed by the administrative authorities. Even if the case is transferred to the court, from the perspective of the judicial authorities’ choice when facing a large number of cases, the fairness and justice expectation given by the judicial power may also be greatly reduced. Faced with plenty of minor criminal cases, the countries adopting the qualitative convicition mode have to turn to criminal penalties by administrative system, like the system of petty crime diversion and traffic violation notice in Japan. We should not abandon our traditional legal culture completely such as ‘the law does not punish numerous offenders’ , while the treatment of tradition should be considered as a process of sublation.Both the experience of legal construction since 1949 and the requirement of social governance at the present stage need for a appropriate reduction of the criminal threshold. In the process of lowering the criminal threshold, it is essential to impose certain restrictions upon minor crimes. In addition, administrative penalties should be imposed on minor illegal acts to maintain the dual sanctions system of administrative penalties and criminal penalties. China’s criminal law should formulate some reasonable and legitimate limitation on the downward trend of the criminal threshold through the constitutionality and public opinion. The crimes involved in the downward trend of the criminal threshold possess a measure of damage to legal interest in the first place. Thus, it is not necessary to use the constitutional relevance of legal interests to perform the task of ensuring the constitutationality in the process of lowering the criminal threshold. The principle of necessity and the principle of balancing should be used to determine whether the criminal threshold should be reduced instead of the principle of suitability. As far as the principle of necessity is concerned, the legislators should decide whether the criminal penality they choose has the least damage to this specific illegal act. In the case of the principle of balancing, for the sake of a type of legal interest, the legislators have to determine whether the criminal penalty has inevitable damage to other legal interests. There is a worldwide tendency that unreasonable and irrational public opinion has a strong influence in the legislation of criminal law. China should insist on a rational response to unreasonable public opinion, forming a rational legislative concept to the public opinion. We should also attach importance to strengthening the empirical research of legislation, improve the legislative process and amend the criminal law by implementing a triple-consideration strictly.