The aim of this study is to investigate the relationship between online gaming behavior and special underlying social group structures through the use of player information of a certain MMORPG. Data were collected from the logs of an MMORPG in 2011, recording five types of gaming behaviors, player gender, avatar gender and avatar occupation types to investigate whether different avatars affect gaming behavior. This study includes 1,727 male players and 656 female players. The results indicate that the six-cluster model has the goodness of model fit. Different clusters differ in the five different types of gaming behaviors and the choice of avatar gender and occupations. This result shows that different avatar roles will influence players' gaming behaviors.