Objective To compare the diagnostic accuracy of conventional urodynamic (CUD) and ambulatory urodynamic monitoring (AUM) in diagnosis of female stress urinary incontinence (SUI).Methods Forty women with SUI were prospectively enrolled and performed urodynamic studies after the ICI-Q-SF questionnaire.According to clinical symptoms,patients were divided into three groups:mild,moderate and severe group.Half patients in each groups performed CUD exam,and the other half of patients performed AUM exam.And two micturition cycles were recorded during AUM.Results There were no significant differrences in age,pregnant production times and ICI-Q-SF score between two groups.Three patients with SUI symptoms had negative findings in AUM group and 15 patients in CUD group (P＜0.05).Among women with SUI,1 1 patients had positive findings in AUM group and 2 patients in CUD group (P＜ 0.05).Conclusion AUM can provide objective evidence for the majority of patients with SUI than CUD.