〔Abstract〕 Objective To investigate the changes and recovery of gut microbiota in rats after broad-spectrum antibiotic exposure and its effect on cognitive behaviors. Methods Rats were randomly divided into antibiotic(AT) group and control group.AT group was treated with antibiotic cocktail containing ampicillin, ancomycin, metronidazole and imipenem for 3 days, and control group was gavaged with the same amount of normal saline.On the 4 th day(24 h after the last antibiotic treatment) and 2 months, feces were collected for 16 S rRNA gene sequencing to detect the changes of gut microbiota; At 2 months, the cognitive behaviors were detected by operant-based delayed matching to position(DMTP) task and Y maze. Results On day 4,the gut microbiota in AT group decreased, including a decrease in microbiota diversity(P<0.000 1),a reduction ofBacteroidetes(P<0.000 1) andFirmicutes(P=0.000 1),and an increase ofProteobacteria(P<0.000 1).After discontinuation of antibiotics, the microbiota began to recover, which had no difference from control group at 2 months.And there was no significant difference in cognitive behaviors between AT group and control group. Conclusion The broad-spectrum antibiotics can decrease gut microbiota in rats.However, this decrease is temporary.The microbiota returns to normal at 2 months after discontinuation of antibiotics.And it does not affect the cognitive behaviors of rats.