The great use of slack resources will give firms some guide to take part in philanthropy to improve performance. Based on the model of “slack resource, corporate philanthropy and organization performance”, this paper explores the relationship among them through the regression analysis. The empirical results based on 176 firms in Shanghai indicate that: unabsorbed slack promotes corporate philanthropy; corporate philanthropy and organization performance has notable positive correlation and the different philanthropy; characteristics have different effects on organization performance; corporate philanthropy mediates the relation between slack resource and organization performance. This research develops the literature of corporate philanthropy and organizational slack, and has some theoretical and practical meanings.