Abstract: OBJECTIVE To establish an experimental murine model of intra-abdominal infection with Pseudomonas aeruginosa early biofilm (BF) and explore the effect of baicalin combined with meropenem on intra-abdominal early BF infection with P.aeruginosa. METHODS With the infusion tube set as the carrier, the PA01 wild strains taken as the experimental strains, 32 female mice were randomly divided into the blank control group, the MEM group (50 mg/Kg·d), and the Baicalin(60 mg/Kg·d) plus MEM(50 mg/Kg·d) group, the intraperitoneal injection of the above drugs was conducted after the model of mice with intra-abdominal Bf infection was established, the blank control group was treated with same amount of sterile saline.The viable bacterial counts on the carriers' surfaces were determined by serial dilution after the drug action for 24 hours, and the morphological changes of the BF on the surfaces of the carriers were observed by means of scanning electron microscopy (SEM). RESULTS The bacterial colony counts on the carriers' surfaces were less in the single drug action group or the combined drugs action group than in the blank control group after the drug intervention for 24 hours (P＜0.01).The bacterial colony counts were less in the MEM group than in the Baicalin group (P＜0.01); the bacterial colony counts were remarkably less in the Baicalin plus MEM group than in the Baicalin group and the MEM group (P＜0.01).The SEM observation revealed that the bacterial BF formed on the surfaces of carries was more and thicker in the blank control group than in the Baicalin group, the MEM group, and the Baicalin plus MEM group and was thinner in the MEM group than in the Baicalin group; the biofilms of the Baicalin plus MEM group were almost destroyed and cleared, only a small amount of P.aeruginosa strains could be seen. CONCLUSION Baicalin has the destructive effect on early BF of the intra-abdominal P.aeruginosa in the mice, and its combination with MEM may intensify the bactericidal action against BF.