Objective: To identify the HIV transmission in discordant couples and the epidemic characteristics of concordant couples related to HIV infection., Methods: HIV/AIDS database was down-loaded from AIDS information reported system for analysis. Patients with HIV-negative couples between 2009 and 2013 in Zhejiang province were enrolled in this study. Information included demography characteristics, highly active antiretroviral therapy (HAART), HIV incidence rate and risk factors, characteristics on HIV concordant couples., Results: The HIV incidence rate on HIV-negative couples of 2 575 HIV/AIDS was 3.56 per 1 000 person-year, reducing from 5.49 per 1 000 person-year in 2009 to 3.20 per 1 000 person-year in 2013. There was a slight increase on HIV incidence rate among couples in those HIV-positive men who were heterosexual, while it decreased among couples of HIV-positive women. Initiation of HAART over 1 years (OR = 0.063, 95% CI: 0.019-0.204) seemed to be a preventive factor for HIV transmission between the couples under study. Factors as history of infection longer than 3 years (OR = 3.564, 95% CI: 1.296-9.804) and beingnon-local resident (OR = 2.626, 95% CI: 1.098-6.230) were risky factors., Conclusion: The incidence rate of HIV transmission between HIV discordant couples was low but imbalance in different areas. People who were non-local residents under HIV discordant status, would need more attention. HAART, time of infection, status of residency appeared risk factors for HIV transmission within the couples.