Many studies in the recent years have investigated lexical collocations but few of them directly measured learners production of lexical collocations and seldom concentrate on the relationship between learners ability to use lexical collocations appropriately and their writing fluency.The present study intends to explore college EFL students actual use of lexical collocations in terms of frequency and variety in their English writing (i.e.,online writing and process writing) and further,to find out the connection between the use (i.e.,frequency and variety) of lexical collocations and writing fluency.