Abstract: Objective To explore the association between sexual sensation seeking and the situation of having sex with men for the first time among young men who have sex with men (YMSM). Methods YMSM were recruited through online publicity, organization of outreach activities together with HIV voluntary testing services. And they were investigated via anonymous questionnaires. Results A total number of 375 valid questionnaires were received.The first gay sex age was (18.98±2.11), 83.38% happened by mutual consent, 61.93% had sex with man who was older, 50.94% used condoms for the first time, 35.12% chose friend as the first sexual partner. Results from partial correlation analysis showed that sexual sensation seeking was negatively correlated with the first gay sex age and condoms using (r=-0.171 and -0.248,respectively). The multinomial logistic regression results showed that every point increasing of sexual sensation seeking score indicated that the possibility of the first gay sex age dropped from 20 and above to 18~20 and less than 18 increased 0.065-fold and 0.109-fold respectively (OR=1.065,95% CI:1.016-1.117; OR=1.109,95%CI:1.046-1.175). And the possibility of the first gay sex without using condoms increased 0.070-fold (OR=1.070, 95% CI:1.034-1.107). On the contrary, those who owned lower sexual sensation seeking score tended to choose friends rather than encounter sexual partners when having sex with men for the first time (OR=0.936, 95% CI:0.900-0.974). Conclusions YMSM who owned higher sexual sensation seeking score were younger and tended to choose encounter sexual partners when having sex with men for the first time. They were also more likely to have sex for the first time without using condoms.