Abstract：In written language, the English noun phrase is an important part of a sentence. They carry a large amount of semantic information. English learners’ lack of knowledge about noun phrases not only affect their reading comprehension and writing competence, but also easily lead to convey the ideas incorrectly in the paper. Nevertheless, the complexity, variation and accuracy of NPs always hinder the learners’ use of NPs to some degree. Therefore, to increase the learners’ awareness of the importance of NPs plays a key role in improving of their English ability. 

　　　The thesis, choosing English majors in our college as research subjects, extracts 160 pieces of compositions (40 compositions randomly from each grade) as the samples, combining quantitative and qualitative analysis, to analyze the use of noun phrase in the views of the complexity, diversity, and accuracy in the second language acquisition. Through the investigation the author found that: (1) English majors in our college overuse the NP1 (NP with only a noun as head) in four types of noun phrases but the other kinds of NPs can't be utilize fully; (2) The students put more attention to the complexity and accuracy, and did not fully realize the importance of variation; (3) The amounts of NP1 used by our college English major runs down steadily while the number of NP2(NP with pre-modifiers), NP3(NP with post-modifiers) and NP4(NP not only with pre-modifiers but also with post-modifiers) used by our college English major increases slowly. What’s more, the peak of the use of NP2 and NP4 is in grade three, while NP3 is in grade four.

　　　In addition, possible reasons are also analyzed as follows: (1)The effects of negative native-language transfer;（2）Their ignorance of a relation of opposition and unification of the three dimensions ;（3）Their language proficiency levels .Finally, based on these findings, properly pedagogical advices on noun phrase teaching are provided as well as the limitations of the research. 

Key words:  noun phrase  complexity  variation  accuracy

摘要：在英语写作中，名词短语是句子的重要组成部分，承载着大量的语义信息。英语学习者对名词短语知识的匮乏不仅严重影响其对英文读物内涵的正确理解，而且极易导致其对思想和认识的错误表达。而在某种程度上，名词短语自身结构的复杂性，多样性和精确性，是影响学习者掌握名词短语的使用。因此，加强对名词短语知识的了解对提高学习者英语水平起到至关重要的作用。

　　　 本文以我校英语专业学生为研究对象，从每个年级中随机抽取四十份作文，共160篇，作为研究的语料，采用定量和定性分析相结合的方法，从名词短语的复杂性，多样性，准确性三个角度对我校英语专业学生二语写作中名词短语的使用情况进行分析。研究发现:（1）我校英语专业学生在使用名词短语四种类型中,过度使用NP1（无限定词引导的名词短语）和未充分使用NP2（带有前置修饰语的名词），NP3（带有后置修饰语的名词短语）和NP4（带有前置修饰语和后置修饰语的名词短语）。（2）高年级的学生把注意力转移到了复杂性和准确性上，而未充分意识到多样性的重要性。（3）我校英语专业学生NP1使用不断减少,四年级降到最低；NP2,NP3和NP4的使用增长缓慢,NP2和NP4的使用高峰期是在三年级,NP3则在四年级。

　　　另外，研究还发现造成以上情况的原因有：（1）母语的负迁移影响；（2）学生忽视了名词短语的复杂性，多样性，精确性的对立统一关系；（3）学习者的英语熟练水平。最后文章还从学生角度对以后的教学活动提出了建议并指出了研究的不足之处。

关键词: 名词短语；复杂性；多样性；准确性