Since the outbreak of Covid-19, the epidemic has been spreading continuously. In the face of such a serious public crisis, all walks of life have contributed their assistance in droves. Research shows that tax policies can stimulate charitable donations to a certain extent. Under the public crisis, China's charitable donation mechanism can be specifically divided into five mechanisms of encouragement, acquisition, use, return and supervision. Tax affects the operation of the charitable donation mechanism through the positive role of support, guidance, allocation, guarantee and supervision to encourage the public to participate more in charitable donation. At the same time, however, problems such as charity fraud, material allocation not in time and complicated personal donation deduction are also gradually exposed. In this regard, measures such as timely updating relevant information, increasing support for direct donations, and carrying out pre-tax deduction declaration agency can be taken to further improve China's charitable donation mechanism and improve the national crisis management capacity.