【Abstract】 Objective To compare the effect of saline and heparin sodium saline on urodynamic study. Methods 90 patients undergoing urodynamic examination in the hospital from March 2015 to May 2016 were randomly divided into the control group (flushing the pipe with normal saline) and the study group (flushing the pipe with heparin sodium saline), 45 patients in each group. Changes of coagulation indexes ［prothrombin time (PT), activated partial thromboplastin time (APTT)］, platelet count (PLT) and visual analogue scores (VAS) in the two groups before and after examination were observed. The catheter use time, catheter sealing time, bleeding rate, plugging rate and the incidence of catheter related complications were compared between the two groups. Results There was no significant difference in PT, APTT, PLT and VAS score between the two groups before examination (P＞005). After examination, the PT and APTT only in the study group were significantly prolonged, and the changes of PT and APTT in the study group were significantly greater than those in the control group (P＜005). However, there was no significant difference between the two groups in PLT after examination (P＞005). VAS scores of the two groups at 1 day, 3 days and 5 days after examination were significantly lower than those before the examination, and the decrease in study group was significantly greater than that in the control group (P＜005). The catheter use time and sealing time of the study group were significantly shorter than those of the control group (P＜005). The plugging rate and the incidence of catheter thrombosis in the study group were significantly lower than those in the control group (P＜005) but there was no significant difference in the incidence of bleeding, catheter dysfunction and catheterrelated infections between the two groups (P＞005). Conclusion The application of heparin sodium saline has more advantages over normal saline in clinical urodynamic examination in anticoagulation, relieving pain of patients, shortening the catheter use time and sealing time and reducing the plugging rate and the incidence of complications under the condition of not increasing the risk of bleeding.