Abstract. Considering that achievement motivation is an important variable to explain human behavior, the characteristics of online games can potentially stimulate motivation in some people. The online game Dota 2 has such characteristics as widespread popularity, high and varied complexity and openly accessible data on its participants’ behavior. For the first time, in focusing on the specific behavior and achievement motivation of college students who have played the online game Dota 2, this study utilized a quantitative methodology to study the relationship between them. Based on the achievement motivation scale and structural equation model, this study found that the overall achievement motivation of college students is weak, and reached the conclusion that the total achievement motivation is negative which is obviously different from the previous researches. Achievement motivation has significant influence on online game behavior, and it has both direct and indirect effect on the core behavior of players.