Abstract: Based on the perspective of stakeholder theory, the study distinguished internal and external social responsibilities according to whether there was a formal contractual relationship or not. We chose 3 759 private enterprises as the sample and explored the effects of family involvement on internal and external social responsibilities and the behavior patterns of internal and external social responsibilities at different stages of development. The results show: firstly, family involvement increases external charitable donation, but it inhibits enterprises' internal staff welfare investment. Secondly, compared to mature enterprises, the positive relationship between family involvement and charitable donations becomes stronger in newly-built enterprises, but the negative relationship between family involvement and staff welfare is not changed. At last, when the human capital of entrepreneurs is stronger, the negative relationship between family involvement and staff welfare becomes weaker. After controlling the sample selection bias and substitute variable, our conclusions are still robust. The results reveal that family enterprises follow different behavioral logic when they undertake internal and external social responsibilities, and tend to give priority to external social responsibility.