ObjectiveTo understand the antimicrobial resistance of common clinical pathogens to antimicrobial disks containing different ratios of cefoperazone/sulbactam, so as to provide basis for rational application of cefoperazone /sulbactam in clinic. Methods1 141 pathogens isolated from clinical specimens in a hospital in the first half year of 2014 were collected, disk diffusion method was adopted to detect antimicrobial activity of two kinds of cefoperazone/sulbactam disks (70/35 μg and 75/75 μg).ResultsOf 1 141 pathogenic strains, 675 （59.16%）were Enterobacteriaceae, 447 (39.18%) were nonfermentative bacteria, and 19 (1.66%) were other gramnegative bacilli. Resistance rates of pathogens to 70/35μg and 75/75 μg cefoperazone /sulbactam antimicrobial disks were as follows: extendedspectrum βlactamases(ESBLs)producing Escherichia coli (n=221) were 7.69% and 2.26% respectively, ESBLsproducing Klebsiella pneumoniae(n=92) 10.87% and 3.26% respectively, imipenemresistant Acinetobacter baumannii（IRAB,n=295）54.92％ and 11.19％respectively；there were significant differences in antimicrobial activity between two ratios of antimicrobial disks(P<0.05). While antimicrobial resistance rates of ESBLsnegative Enterobacteriaceae (Escherichia coli,n=135; Klebsiella pneumoniae, n=98),  imipenemsensitive Acinetobacter baumannii (ISAB, n=51), Pseudomonas aeruginosa (n=48 ), and Stenotrophomonas maltophilia (n=22) were not significantly different (all P>0.05). ConclusionAntimicrobial activity of two different ratios of cefoperazone/sulbactam antimicrobial disks to ESBLsproducing Enterobacteriaceae and IRAB is different, attention should be paid to ratios of cefoperazone/sulbactam during the treatment , so as to achieve the desired therapeutic effect.