会计稳健性作为一项重要的会计信息质量特征，已经影响会计实务至少500年。2005年，FASB和IASB提出放弃稳健性原则，这引发了国内外学者研究会计稳健性的兴趣，使其成为会计领域最热门的实证研究话题之一。现有的关于会计稳健性的研究主要是围绕为何会形成以及如何加以计量，而对其经济后果的研究较为缺乏。前期研究表明，我国企业中投资效率低下的现象比较常见，具体表现为投资过度或投资不足，会计稳健性能否有效地发挥治理职能，从而改善企业的投资效率值得探究。因此，本文将会计稳健性区分为条件稳健性与非条件稳健性，以投资效率为切入点，基于信息不对称与委托代理理论，深入研究这两种稳健性对企业投资效率的作用机理。 本文选用2003至2012十年间在沪市、深市交易的A股公司作为观测样本，利用多元线性回归方程检验会计稳健性与投资效率之间的相关关系，并进一步考察股权分置改革对会计稳健性作用发挥的影响，研究发现：（1）会计稳健性在整体上降低了上市公司的投资效率，这种影响主要来源于非条件稳健性，条件稳健性无显著作用；（2）股权分置改革能够提高上市公司的投资效率，但没有显著改变会计稳健性对投资效率的作用。在上述研究的基础上，本文进一步讨论了会计稳健性对投资过度、投资不足的影响，研究结果如下：在投资过度的情况下，非条件稳健性进一步刺激了投资，条件稳健性则有效地抑制了投资；在投资不足的情况下，两种稳健性均造成企业的投资水平更低。据此，本文建议，我国会计准则制定机构应当充分考虑会计稳健性的经济影响，对条件、非条件稳健性加以权衡，从而在准则中做出恰当、合理的要求。另外，国内企业在确定稳健的会计政策时，应当全面考量这两种稳健性的成本和收益，结合自身情况适当运用稳健性原则。

As an important quality characteristic of accounting information, accounting conservatism exists for more than 500 years in accounting practice. In 2005, the FASB and IASB published a joint statement which suggested to abandon the conservatism principle. This made conservatism become one of the most controversial issues again. Existing research about accounting conservatism mainly focuses on motivation and measurement methods. However, research about the economic consequences of accounting conservatism is relatively scarce. Previous studies show that over-investment or under-investment caused by agency problem and financial constraints is common in China's enterprises. Does accounting conservatism have a positive economic consequence? Based on the information asymmetry and agency costs theory, we distinguish the role of conditional conservatism and unconditional conservatism and study their impact on investment efficiency. This paper takes the Chinese listed company 2003-2012 as a sample and then tests the relationship between accounting conservatism and investment efficiency by multiple linear regressions. And we also concern the influence of Stock Right Decentralized Allot Revolution to extend the research. The conclusions are as follows: (1) The overall conservatism has negative impact on investment efficiency and this effect is mainly from unconditional conservatism. The effect of conditional conservatism on investment efficiency is not obvious. (2) Stock Right Decentralized Allot Revolution can increase investment efficiency, however it doesn't significantly change the relationship between conservatism and investment efficiency. In addition, through the further tests of conservatism and over-investment/under-investment, this study finds: Unconditional conservatism can exacerbate over-investment and under-investment. While conditional conservatism can alleviate over-investment and exacerbate over-investment. So the overall conservatism will exacerbate over-investment and under-investment. Accordingly, we suggest that accounting standards board should fully consider the impact of conditional conservatism and unconditional conservatism, so as to make appropriate and reasonable requirements in accounting standards. In addition, China's listed companies should weigh the costs and benefit of the two kinds of conservatism while determining the accounting policies and properly use the principle of conservatism based on their own circumstances.