Although abundant research has explored the relationship between social class and prosociality, it remains controversial. This study aimed to investigate the effect of social class priming on prosociality among college students. Experiment 1 was an explicit experiment in which we employed the MacArthur scale to prime participants’ social class and then used a donation task. The results showed that students in a low social class priming group had more donation behaviors compared to ones in a high social class priming group. Experiment 2 was an implicit experiment in which we used a single category implicit association test (SC-IAT) to investigate the relationship between the self-concepts of different social classes and prosociality after priming participants’ social class. The results indicated that students in a low social class priming condition had a stronger connection between self-concepts and prosocial inclinations than ones in a high social class priming condition. Thus, our study demonstrated that students primed with low social class were more prosocial than those primed with high social class, and supported the empathy-altruism theory of prosocial behavior. These findings are of great practical significance to promote prosocial behavior of individuals of different social classes.