Through a word guessing test and a word guessing strategy questionnaire,this paper makes a comparative analysis of the word guessing ability and the word guessing strategies between 60 college English learners with larger vocabulary size and smaller vocabulary size.The results indicate that the effects of vocabulary size on words guessing ability are significant,and there are differences in words guessing strategies by English learners with different vocabulary size.Based on the results,some suggestions are put forward to improve the college English teaching.