Abstract: The nuclear island buildings of HTR-PM adopts reinforced concrete slab and shell structure. It is nuclear safety related, and the seismic classification is class I. When the nuclear power plant is subjected to the ultimate safe earthquake (SL-2) (once every 10 000 years), the structure is in the state of basic elasticity, and when it is subjected to the safe earthquake (SL-1) (once every 500 years) or below, the structure is in the state of complete elasticlity. Through the quasi-static tests of shear walls, the limit value of displacement angle was obtained and had been used as the control index of structural performance; at the same time, the calculation method of seismic response of the nuclear island buildings and the calculation formulas of in-plane bearing capacity of reinforced concrete slab shell structure were proposed. The above seismic performance objectives and design methods were adopted in the seismic design of the nuclear island buildings. Finally, through shaking table tests, it was proved that the nuclear island buildings with seismic design method proposed in this paper had good seismic performance and could meet the requirements of nuclear safety function. The calculation formulas of in-plane bearing capacity of reinforced concrete slab and shell structure proposed in this paper had been adopted by relevant standards.