Objective:To investigate the variation of the drug resistance of Escherichia coli(Eco)against antibacterial in clinical specimens in the hospital, and to evaluate the simultaneous use of antibacterial, to explore to provide the reference for the reasonable clinical use of antibacterial. Method:Eco was separated from all kinds of clinical specimens of out-patients and in-patients in the hospital from August of 2005 to April of 2006,and ESBLs was detected with Kirby-Bauer (K-B) disk diffusion method. It was also counted that the antibacterial drugs ranked the first 30 in sales per month and their use frequencies in the same period in the hospital. Result:The detectable rate of producing ESBLs Eco was 58.6%. Eco was completely sensitive to imipenem. It had lower resistance rates, only 2% and 4% , against piperacillin/tazobactam and cefoperazone/sulbactam; and had 59% and 55% resistance rates respectively against cefotaxime claforan and ceftazidime pentahydrate in the third generation cephalosporin. The third generation cephalosporin and quinolones kept high in sales and their use frequencies ranked the first three. The use of the third generation cephalosporin with anhydrase inhibitors also had an uptrend. Conclusion:There is a direct relation between the use of a great deal of antibacterial and the imitative drug resistance of Eco. It is necessary to strengthen its clinical management and to raise the level of drug use.