Objective:To improve the latent syphilis diagnostic criterion through investigating 836 cases of latent syphilis. Methods:Collecting the data of 836 cases of latent syphilis in 6 national sexually transmitted diseases (STD) sentinel surveillance in Jiangsu province from 2008 to 2010,moreover,the serums of the cases were collected to check the diagnostic veracity with non treponemal antigen serological test (TRUST) and treponemal antigen serological test (ELISA). Results:The average age of 836 cases latent syphilis was(42.65 ± 13.26) years old;87.92% cases of the latent syphilis were came from comprehensive medical institutions;82.66% cases were checked out with to be hospitalized;55.86% cases were firstly treated with penicillin;92.35% cases were ELISA and TRUST positives simultaneously and 27.28% cases of TRUST titer were more than 1∶8. Conclusion:In order to attain the aims of prevention and control of syphilis in planning of China(2010-2020),the diagnosis and therapy abilities of latent syphilis must be improved.