Objective To understand the syphilis infection status and its influencing factors in drug-drug detoxification populations; Methods The population of the Yixing City Drug Rehabilitation Center in Jiangsu Province was selected for drug detoxification. The antibodies were detected by the syphilis particle agglutination test, and the basic information, drug abuse and sexual behavior were investigated using a questionnaire. Results Among 790 people, 133 cases of syphilis antibody were found to be positive. The syphilis infection rate was 16.8%. The average age of syphilis group (P<0.001) and the average age of starting drug use (P=0.002) were higher than those of non-syphilis group. There was a difference in sexual partner between the two groups. (P=0.044); multivariate analysis showed that The average age of syphilis group (P<0.001) and the average age of starting drug use (P=0.002) were higher than those of non-syphilis group. There was a difference in sexual partner between the two groups. (P=0.044); multivariate analysis showed that older people were more susceptible to syphilis infection (OR=1.053, 95% CI: 1.019-1.087), and temporary sexual partners were more susceptible to syphilis infection than stable partners. (OR=1.900, 95% CI: 1.183-3.050). Conclusion The syphilis infection rate is high in this population, and the risk factors for syphilis infection in unsafe sexual behavior.