Objective To explore species distribution of bacteria colonizing the indwelling double J tube in pregnant women. Methods From March 2013 to December 2017, patients with double J tube during pregnancy in urology department of a hospital were collected. According to the time of indwelling double J tubes, they were divided into group A (indwelling time ≤ 1 month) and group B (indwelling time >1 month). All patients underwent bladder urine and double J tube bacterial culture before and after extubation. Species and positive detection rates of bacteria in bladder urine and double J tube between two groups were compared and analyzed. Results A total of 237 pregnant women with ureteral obstruction were included in the study, 129 cases in group A and 108 in group B. A total of 78 strains of bacteria were isolated in double J tube culture, 35 strains in group A and 43 in group B. Gram-negative bacilli were predominant in both groups, accounting for 54.29% and 67.44% respectively, followed by gram-positive cocci, accounting for 37.14% and 25.58% respectively; isolated bacteria were Escherichia coli (n=30), Enterococcus spp. (n=12), Staphylococcus spp. (n=12), Klebsiella pneumoniae (n=11), Pseudomonas aeruginosa (n=7) and so on. Positive rate of double J tube bacterial culture was higher than that of bladder urine culture in both group A and group B, difference were both statistically significant (both P<0.05). Positive rate of double J tube bacterial culture in group B was higher than that in group A (39.81% VS 27.13%, P<0.05), but there was no significant difference in the positive rate of bladder urine culture between group A and group B (P>0.05). Conclusion The main colonized bacteria for pregnant women who are inserted double J tubes are gram-negative bacilli, the longer time the double J tube is placed, the higher rate the bacteria colonize and the higher positive of bacterial culture.