The purpose of this research is to explore the relationship between the family business and corporate social responsibility (CSR) and to further study whether the effect of overconfidence of family business CEO on CSR performance will strengthen (weaken) the convergence of interest effect or strengthen (weaken) the entrenchment effect. During the sample period of this paper, there were 11 financial years from 2007 to 2017, with the public companies in Taiwan. The results show that family firms have worse CSR performance than non-family firms, which supports the entrenchment effect. In addition, this study finds that the overconfident CEO of family business will enhance the entrenchment effect of the family business, that is, the overconfident CEO of family business will lead to worse corporate social responsibility performance.