Abstract: ObjectiveTo investigate the changes in the knowledge and behaviors about human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) prevention and control among the men who have sex with men (MSM) after HIV-positive notification.MethodsFace-to-face questionnaire surveys were conducted among 94 HIV-positive MSM recruited at a HIV voluntary counseling and testing (VCT) clinic in Nantong city before and 6 months after the HIV-positive notification during January 2005 and September 2013.ResultsAmong the MSM,the awareness rate of HIV/AIDS knowledge increased significantly after the notification (from 84.04% to 97.85%,χ²=8.847;P<0.01),especially among the MSM with the education of junior high school or below (from 75.00% to 95.00%,χ²=4.021;P<0.05).There were significant changes in the patterns of homosexual anal sex (χ²=14.270,P<0.01) and significant increase in the ratio of condom use in every sex behavior (from 5.74% to 72.73%,χ²=154.183,P<0.05),but no significant change in the number of sexual partners was observed after the notification.For the MSM with commercial homosexual behaviors,the number of sexual partners decreased (χ²=9.090,P<0.05),but the ratio of condom use in every sex behavior increased significantly (from 11.76% to 71.43%,χ²=7.391,P<0.05);while no change in the patterns of anal sex was observed after the notification.For the MSM with heterosexual sex,the ratio of condom use in every heterosexual behavior increased significantly (from 42.50% to 82.40%,χ²=7.400,P<0.05).ConclusionThe HIV-positive MSM in Nantong city had a relative high HIV/AIDS knowledge and had decreased high risk sexual behaviors after HIV-positive notification.