Objective:To explore the incubation period and the influencing factors of HIV infection among men who have sex with men(MSM) in Jiangsu. Methods:An ambispective cohort study was conducted to collect a HIV infection and AIDS cases in two cities in Jiangsu Province with certain time mark of infected and onset. The average incubation period was calculated by Kaplan-Meier product-limited method. Cox regression model was used to explore the influencing factors. Results:The average incubation period of HIV infection was(46.129 ± 2.795) months,95%CI was 40.651-51.606 months,among MSM with HIV/AIDS through homosexual transmission in Jiangsu. COX proportional hazards regression model showed that higher CD4 counts at baseline and 6 months after diagnosis were the protective factors of incubation period. Conclusion:Incubation period of homosexual transmission AIDS may be lower than that of other previously reported data. The present study suggested that it was important for public halth service institutes to provide proper service for the early treatment of MSM infectors to prolong their survival time and to improve their survival quality.