Abstract: The containment pressure rises rapidly after LOCA, especially for the small reactors containment with very small free capacity, in order to avoid the rapid rise of containment pressure in the short term after LOCA, a pressure suppression system should be arranged in the containment. In this paper, the GOTHIC program was used to model the containment with pressure suppression system, and sensitivity analysis was carried out on the thermal response of containment after LOCA under different configuration schemes of pressure suppression system, the demonstration method of containment capacity with pressure suppression pool system and the optimal scheme were obtained. The analysis results show that the pressure suppression pool can significantly reduce the pressure in the containment, the pressure in the containment varies greatly under different configurations of pressure suppression pool modules, and the optimal configuration should be carried out for the containment design scheme in the design process.