Four hundred and twenty two patients with ureteral calculi undergoing surgical treatment from January 2016 to December 2016 were enrolled in the study.Urine samples were taken from upper and lower ureter of stone obstruction,pathogen examination and drug susceptibility tests were performed.Twenty nine strains of pathogens were isolated from the upper segment of ureter with a detection rate of 6.9%;22 strains were gram-negative bacteria(75.9%)and 3 strains were gram-positive bacteria(10.3%)and 4 strains were fungi(13.8%).Forty eight strains of pathogenic bacteria were isolated from the lower segment with a detection rate of 11.4%;37 strains were gram-negative bacteria(77.1%),11 strains were gram-positive bacteria(22.9%),no fungi was isolated.In 20 cases the positive results were obtained only from upper ureter urine samples, and in 39 cases the positive results were obtained only from lower segment samples.The same pathogens were detected from both upper and lower ureter of stone obstruction in 7 cases, and different pathogens were identified in 2 cases.The most common pathogens were Escherichia coli, followed by Proteus mirabilis, Klebsiella pneumoniae, Enterococcus faecalis and Enterococcus faecium.The resistance to quinolones in gram-negative bacteria was higher than that to cephalosporins.The resistance rate of Escherichia coli to cephalosporin was 36.7%-63.3%,that to ciprofloxacin and levofloxacin was 86.7%-100.0%; the resistance rate of Enterococcus to erythromycin was 100.0%.It is suggested that ureteral calculi obstruction may lead to negative culture results of conventional mid-stream urine samples.It is of clinical value to investigate the distribution and antibiotic resistance of pathogens both from upper and lower segments of ureter in patients with ureteral calculi.