Objective: To explore the influence factors，one is excretion group, the other is non-excretion group .Results: 131 cases of 220 cases excrete the calculi natural within 8 weeks.The excretion rate is 59.5% .The blood leukocyte was higher in the excretion group than the non-excretion group.We found that blood leukocyte may be the second factor which influent the excretion rate of ureteral calculi compared to the size of calculi.Conclusion: In addition to the size of ureteral calculi, the blood leukocyte changes may be another factors in combination with size to predict whether the ureteral calculi can excrete spontaneously. on natural excretion of single ureteral calculi and to provide basis for clinical practice. Methods: Retrospective analysis of 230 ureteral calculi patients in our hospital from January 2010 to June 2011.All the cases were diagnosed single ureteral calculi by ultrasound or CT examination.Then we collected the epidemiology, imaging, laboratory examination data . All patients were informed back at 4 weeks and 8 weeks , ultrasound ,blood and urine tests were given at return visit. Patients were divided into two group