Through questionnaire and screening, epidemiology of syphilis in pregnant women and related risk factors were studied, to develop effective policy and reducing the negative impact of the disease. All pregnant women who appeared at the hospitals the first time, were included, in Shenzhen city. Tolulized Red Unheated Serum Test (TRUST) method was used for primary screening and positive results were confirmed by the Treponema Pallidum Particle Agglutination (TPPA) test at the Shenzhen Center for Disease Control and Prevention (SZCDC). Positive patients were informed and treated and the pregnancies were managed accordingly at the SZCDC. From 2003-2005, 418,871 (94.7%) pregnant were screened. Epidemiological and treatment data were collected from 2019 positive cases of infectious syphilis (0.48%). Among them, 94.2% were between 20 and 35 years old, with 93.6% of them had only junior high school education and 63.4% of them worked as commercial services or jobless which was significantly higher than other occupations (OR = 8.628). 89.5% of them were from other cities, significantly higher than from local residents (OR = 8.733). Gestational weeks at original diagnosis was longer and the infection rate higher. The infection rate of syphilis in Shenzhen was still at a high level which was related to occupation, education level, place of residency, gestational weeks at first diagnosis etc. Further screening measures and early intervention were important.