Objective To study the influence of ceftriaxone and imipenem to sepsis in the rat intestinal flora and bacterial drug resistance.Methods 8 rats were randomly included in normal control group from 48 healthy SD,and the rest of them were built the endotoxin sepsis model using 15 mg/kg intraperitoneal injection of endotoxin.According to whether to apply antibiotics and application deadlines in 24 h after modeling,40 rats were randomly subdivided into sepsis without treatment group,sepsis ceftriaxone 3 d group,sepsis ceftriaxone 7 d group,sepsis imipenem 3 d group and sepsis imipenem 7 d group(n=8).During ceftriaxone and imipenem injection treatment,in the corresponding time,colon contents were taken for enterobacteriaceae,enterococcus strains of quantitative culture and bacteria and fungi identification. Results After treatment with antibiotics,the number of rat intestinal bacteria decreased significantly(P<0.05).Ceftriaxone selected pseudomonas aeruginosa and enterobacter cloacae,while imipenem selected klebsiella pneumoniae, proteus and excrement enterococcus conditional pathogenic bacteria.All showed the inclination resistance. Conclusion Ceftriaxone and imipenem antibiotics could decrease the original bacteria number,so pseudomonas aeruginosa and excrement enterococcus conditional pathogenic bacteria could become advantage bacterium group,causing intestinal micro ecological environment disruption.