Abstract: Objective To explore the positive and negative influencing factors of condoms use among young men who have sex with men (YMSM), and to evaluate the effect of HIV/AIDS intervention service. Methods A status survey of 726 YMSM(15-29 age) was conducted by Snowball sampling method in Chongqing, Sichuan and Guangxi provinces,the western of China. The questionnaire was based on the Information-Motivation-Behavior Skills (IMB) Model. Amos 17.0 software was used to build the extend IMB model. Result In the last six months, 59.64% YMSM used condoms every time when they had anal sex, and 57.71% YMSM used condoms during the whole sex process. The extend IMB fit the data well. The influencing factors of condoms use among YMSM were behavioral skills, preventive behavior costs, HIV/AIDS intervention service, preventive knowledge, preventive motivation, degree of education, monthly disposable income, and the total effect coefficient of influencing factors were 0.417,-0.366,0.258,0.141,0.159,0.053, 0.020, respectively. Conclusions HIV/AIDS intervention service have a positive influencing factor to condoms use, but preventive behavior costs inhibit condoms use among YMSM. In the future, the intervention service should carry out risk education, focusing on preventive behavior costs and the fact inadequate knowledge of prevention information, and appropriately strengthen the intensity and the scope of HIV/AIDS intervention service among YMSM.