随着中国英语高考改革的推进，写作部分的占分比率在某些省份已经被提高了。此趋势很有可能会蔓延到更多省份，导致对学生的写作能力要求提高。要提高学生写作能力的前提条件就是了解学生的问题。错误分析就是一个探究学生问题的好途径。因高考英语作文字数要求在100词至150词之间，所以本体错误和语篇错误不明显，而词汇和句法错误占较大比例且可能造成严重错误解读，所以本文旨在分析贵阳某校高三学生的词汇错误和句法错误以便于确定发生频率最高的词汇错误和句法错误，错误产生的原因，以及错误的主要来源。笔者通过调查发现三种由语内干扰引起的词汇错误，十五种由语内干扰产生的句法错误，四种由语际干扰产生的词汇错误，和十七种由语际干扰产生的句法错误。发生频率最高的词汇错误是直译语。发生频率最高的句法错误是词性使用混乱。错误产生的可能的主要原因是以中文语言结构逐字翻译和对英语的掌握程度不足。错误的主要来源是语际干扰。因此，建议老师让学生意识到中文与英文的不同以此来避免他们以中文结构直译。

With the advancement of Chinese national matriculation English test reform, the score proportion of writing part has been increased in some provinces. The trend is likely to spread to more provinces, leading to a higher requirement for students’ writing competence. The precondition to enhance students’ writing competence is to know their problems. Error analysis is a suitable way to investigate students’ problems. Since the word count required by the English test is between 100 to 150 words, substance error and discourse error are not evident, while lexical and syntactic errors account for a large proportion and could cause crucial misinterpretation. Thus, this study aims to investigate lexical and syntactic errors made by senior students of a high school in Guiyang and identify the lexical and syntactic errors of the highest occurring frequency, causes of the errors and the major source of errors. Three types of lexical errors and fifteen types of syntactic errors caused by intra-lingual interference are found. Four types of lexical errors and seventeen types of syntactic errors caused by inter-lingual interference are found. The lexical error of the highest occurring frequency is calquing. The syntactic error of the highest occurring frequency is word class confusion. Literal translation in the form of Chinese structure and inadequate mastery of target language are the main causes of high possibility. The major source of errors is inter-lingual inference. Thus, teachers are suggested to make students aware of the differences between Chinese and English to prevent them from literal translation in terms of Chinese structure.