ObjectiveTo investigate the spatiotemporal distribution characteristics of syphilis epidemic in Mainland China in 2005-2011.MethodsGeographic information system was established based on the data of syphilis epidemic and demographic information from online reporting system of 31 provinces, municipalities and autonomous regions of Mainland China from 2005 to 2011, global indication of spatial autocorrelation(GISA), local indication of spatial autocorrelation (LISA), and spatialtemporal cluster analysis were conducted by GeoDa 0.95i and SaTScan 9.1.1 software, high risk areas of spatialtemporal distribution of syphilis were determined. ResultsThe number of syphilis in Mainland China in 2005-2011 were 1 841 217 cases, annual incidence was 20.07/100 000, suggesting a sign of obvious cluster distribution. Except 2011, GISA coefficient Moran’s I were statistically different. According to LISA analysis, Jiangsu, Shanghai, Zhejiang and Fujian lay in highhigh region in 2005-2009, Chongqing lay in highlow region in 2006-2008, and in 2011, no area was found in highhigh region. Spatiotemporal cluster analysis showed that the most likely cluster was in Shanghai and Zhejiang (2009-2011); the secondary cluster distributed in five areas, including Guangdong, Guangxi and Hainan (2009-2011), Xinjiang (2009-2011), Liaoning and Jilin (2010-2011), Gansu, Ningxia, Shaanxi, Sichuan, Chongqing, Shanxi and Inner Mongolia (2011), Beijing and Tianjin (2008-2010).ConclusionSignificant spatiotemporal cluster pattern is found for the distribution of syphilis in mainland China, which can be meaningful for pertinent control.