Abstract: Objective To learn the epidemic law of STD and provide basis for formulating prevention measures. Methods Using the combination methods of physical examination and experimental test to examine the STD patients in Clinic of CDC of Zhejiang province. Results There were 1 404 STD patients among 5 860 persons who had seeked medical treatment. The prevalence rate was 23.96% . The main kinds of STD included nongonococcal urethritis (Cervicitis) (NGU), Condyloma acuminate and Genital Herpes, making up 94.01% of the patients. The sex ratio of patients was 1.38:1. A concentration of cases (97.36%) occurred at age 20-49. Most of the patients were self- employed laborers,workers,cadres and staffs,making up 71.72%. The rate of married was 63.96%. Sexual behavior with several partners was the main route of STD transmission. Conclusion Disordered sexual behavior was still the main reason of STD prevalence.therefore,clinical monitoring was an effective measure to discover STD at the early stage.