Our society needs "good people", who can help us when we are in trouble and stand up for us when we are in danger. "Good people" are defined as individuals with high-virtuous personality qualities in psychological research. Virtuous personality is a wonderful personality quality, which expresses the positive value orientation in personality, and is a research theme of personality psychology with Chinese cultural characteristics. In today's society, people respect the kindness. Effectively guiding people to make more friendly and altruistic behaviors has become a need of the times. Therefore, it is of great practical significance to explore the effect and the psychological mechanism of virtuous personality. A large number of studies have shown that individuals who are more altruistic in real life have higher levels of Internet altruistic behavior. This suggests that virtuous personality can positively predict Internet altruistic behavior. However, the psychological mechanism between them is still unclear. Previous research has shown that qualities of virtuous are often associated with higher self-control, which in turn promotes altruistic behavior. This suggests that self-control may play a mediating role between virtuous personality and Internet altruistic behavior. In addition, security needs are the most basic needs of human beings, people will engage in more self-interest behaviors when security is threatened, which prevents them from performing altruistic behavior. According to the interaction theory of personality and situation, situational risk, as a situational factor, may moderate the influence of virtuous personality and self-control on Internet altruistic behavior. To sum up, this study constructed a moderated mediation model to explore the psychological mechanism that underlies the relationship between virtuous personality and Internet altruistic behavior and its boundary conditions, namely, the mediating role of self-control and the moderating role of situational risk in a real network environment. In this study, 192 subjects were randomly assigned to situations with different levels of risk by experimental method, and completed the Virtuous Personality Questionnaire, Self-Control Questionnaire and Internet Altruistic Behavior Task. The results indicated that: (1) Virtuous personality positively predicted Internet altruistic behavior; (2) Self-control played a mediating role in the relationship between virtuous personality and Internet altruistic behavior; (3) The direct effect of virtuous personality on Internet altruistic behavior and the path from self-control to Internet altruistic behavior were moderated by situational risk, and these two effects were significant in the risk-free situation. This study investigated the moderated mediation model of self-control and situational risk in the relationship between virtuous personality and Internet altruistic behavior. These findings possess theoretical and practical implications in some extent. At a theoretical level, virtuous personality is a subject of personality psychology with Chinese cultural characteristics. Exploring its effect can enrich and develop the theory of local personality psychology. At a practical level, the results of this study can explain the phenomenon of “why good people sometimes don't do good deeds” in real life. The main reason for the increasing apathy in today's society may not be the fewer good people, but the worse environment. The results suggest that social harmony and stability can be better promoted by purifying social atmosphere, and creating a safe interpersonal environment.