Abstract: The scale-down separate and integral test facilities are of vital significance for the research and development of both large-scale advanced pressurized water reactor nuclear power plants and the related analytical codes. However, the distortions of some phenomena induced by the reduced size have directly affected both the design of the facility and the understanding of the test results. Through the equivalent heat transfer coefficient, the distortion of condensation film heat transfer on the inner side of PCS was assessed. With the use of H2TS scaling method, the effect of this distortion on the modeling of containment pressure change response was analyzed. The results show that the scale-down of a test facility has a conservative influence on the condensation film heat transfer.