Aiming at the problem of zero sequence current protection caused by high voltage built-in transformer, the risk assessment of zero sequence current protection considering the impact of inrush is studied from the system level in order to improve the shortage of existing risk assessment model in the inrush scene. Considering the multiple factors affecting inrush current is not entirely available, a calculation model of malfunction probability considering the completeness of parameters is proposed. When the missing parameter information is not available, the comprehensive weighted misoperation probability is obtained by using the data in the monitoring database of the power grid equipment state and assigning the corresponding weight. On this basis, specific risk indicators and operational suggestions are given. In this paper, a specific example is given to demonstrate the proposed risk assessment method, and the results are consistent with the actual operation of the line and bus action results. This work is supported by Project of State Grid Hubei Electric Power Company (No. 26150515003C) and National Natural Science Foundation of China (No. 51207113).