Abstract: Objective Study on GM(1,1)model fit and presume the trend in resistance of E.coli to Ceftazidime. Methods The realistic data about drug-resistance of E.coli to Ceftazidime were collected from the China National Knowledge Internet(CNKI) during 1996～2008 years.Using GM(1,1)model to fit and presume the drug-resistance data. Judging the fitted Results by RSE, MAD and ARE. Results 386 papers and 910 data were collected from CNKI about drug-resistance of E.coli to Ceftazidime during 1996～2008 years in China. GM(1,1)model fitted Results show minor value in RSE, MAD, ARE and high accuracy. GM(1,1)model presume Results show a quickly increasing trend in drug-resistance of E.coli to Ceftazidime in next five years. Conclusion The drug -resistance of E.coli to Ceftazidime show a increasing trend during 1996～2008 years in China. GM(1,1)model could fit and presume the resistant trend very well. GM ( 1,1) model presume Results suggest that clinician should consider strengthening the combination therapy, appropriating replacement drugs to prevent the increasing of drug-resistance and reduce waste of resources.

Key words: GM(1,1)model, drug-resistance, fit, presume