Abstract: Choosing 2008-2015 Shanghai and Shenzhen A-share market of listed companies as the research samples, the relationship among tax burden, charitable donation and enterprise financing constraint was studied with OLS regression model. The results show that:The charitable donation has mitigated enterprise financing constraint; compared with those of non-political connection enterprises, the charitable donation of political connection enterprises has more effective mitigation of financing constraints; When the tax burden is at a high level, the mitigation effect of charitable donation on enterprise financing constraint will be strengthened, which is more prominent in the non-political connection enterprises.