At the intermediate stage, the Chinese college EFL learners are apt to misuse English vocabulary under the influence of the L1. The researcher presents a qualitative study of college EFL learners interlanguage vocabulary and explains how they are influenced negatively by the L1 from semantic and cognitive point of view.Sample sentences with lexical misuses are collected from the data of the EFL learnerscorpus and they are sorted and analyzed on the English-Chinese contrastive basis. The misuses are discussed from five respects: misuses caused by non-correspondence in semantic structure between English and Chinese; misuses caused by different collocations of semantically corresponding words; misuses caused by different syntactic usages of semantically corresponding words; misuses caused by different lexicalization patterns of L1 and L2 and misuses caused by different ways of metonymy. The analysis of the data reveals the causes of the misuses and mismatches,different lexical characteristics of L1 and L2, and different cognitive viewpoints.