Abstract: Reliability of power system is facing severe challenges due to the full accommodation of renewable energy. In this paper, on the basis of the long-term reliability assessment of north American bulk power system, the main factors affecting the reliability of power grid are discussed, and the influence of renewable energy on power system reliability is analyzed. Finally, according to current situation of power system planning and operation in China, suggestions are put forward for improving the reliability standard, integrated design of power grid and full accommodation of renewable energy.