This paper delves into the central position of online games in contemporary society and their close relationship with social interaction. With the popularity of the Internet, online games have become one of the most important ways of leisure and social communication. The study outlines the development of MMOs, from their origins to their diverse classifications, and in particular how their unique social characteristics facilitate interactions between players. Through theoretical analysis combined with social exchange theory and symbolic interaction theory, this paper reveals the mechanisms of social interactions in MMOs, including inter-player exchanges, cooperation and competition, and explores how these interactions profoundly affect players' gaming experience and behavioural decisions. Further, this paper analyses the trend of convergence between online games and social networks, and how this convergence enhances the social attributes and player engagement of games. At the same time, the paper also focuses on the social problems that online games may bring, such as Internet addiction and social disorders, cyberbullying, etc., and looks forward to the impact of technological advances on future social interaction patterns. Finally, the paper summarises the potential and challenges faced by online games in promoting healthy social interactions, and puts forward suggestions for future research with a view to promoting the healthy development of the field of online games and social interactions.