Altruistic behavior is of great significance for individual happiness and social development. The study has focused on the influence of two factors at the individual level on college students’ altruistic behavior. The self-report questionnaires of 2,272 college students on belief in a just world, empathy and altruistic behavior were investigated. The results of the study found that: 1) Just-world belief and empathy both positively predicted altruistic behavior; 2) Empathy influenced altruistic behavior through just-world belief. And from the perspective of motivation theory, it explains that individuals affirm that altruistic behavior will bring spiritual pleasure, so individuals will maintain the consistency of their own internal factors to promote altruistic behavior.This study enriches the research value of altruistic behavior at the individual level and provides an empirical basis for the cultivation of altruistic behavior at the individual level.