Abstract: Based on the system engineering, the system design is conducted for the emergency core residual removal system of HPR1000 nuclear power plant. Considering the requirements of safety, the economic efficiency and technology maturity, the systematic evaluation index system is constructed with the objective of optimizing the engineering application and overall technical index of the nuclear power plant. The optimal emergency residual heat removal system is obtained using AHP method. The results show that it is a optimal solution to eliminate the turbine auxiliary feedwater and extend the function of PRS to deal with the operation events and design benchmark accidents.