Abstract: Reliability assurance program for the nuclear power plant plays an important role in promoting the reliability, availability, maintainability and economy of equipment. During the design process, the feasible reliability performance indicators of SSCs can be defined through the analysis and categorization of risk-important SSCs, and the accumulated reliabilities of SSCs can be highly improved  by the strict quality control means during the following phases, thus to improve the safety and economical performances of nuclear power plants. By analyzing the requirements of the reliability laws and regulations at home and abroad, and embracing the latest research results and technical insights, the key elements of reliability assurance program for designing were given out, the relevant reviewing problems were analyzed and discussed, in addition some suggestions were put out for designing units and regulation agencies.