The use of collocations will affect the accuracy and idiomaticity of a piece of writing. The present paper analyzes and traces the causes of two types of lexical collocation errors by advanced learners in Chinese Learners English Corpus(CLEC): verb + noun and adjective+ noun collocation errors. It is found that for the verb+ noun collocation errors though it is the noun decides the meaning of the collocation, the inadequate combinations of verb+noun undermines the accuracy of writing to a large extent. For ...