As an important means of fulfilling social responsibility, the Corporate Volunteer Program (CVP) is increasingly valued by enterprises. Based on the data collected from 261 employees who have volunteering experiences, this paper introduces a conceptual model of the effects of volunteering on organizational loyalty regarding organizational identity as a mediator and perceived organizational support as a moderator. The results reveal that: employee volunteering has a significant positive effect on organizational loyalty; organizational identity has a significant positive effect on organizational loyalty; organizational identity plays a mediation role in the relationship between employee volunteering and organization loyalty; perceived organizational support plays a moderate role in the relationship between organizational identity and organizational loyalty, and also moderates the mediating effect of organizational identity between volunteering and organizational loyalty.