 Phase change materials are used in passive solar house construction with light steel structure walls which can overcome the problems of weak heat storage capacity and poor utilization of solar heat and effectively solve the thermal defects of light steel structure walls. Based on this, on the basis of preliminary experimental research, this study further carried out theoretical analysis and simulation research on the thermal performance of a light steel structure passive solar house, tromped form, with PCM walls. Through the heat balance analysis of heat transfer in the heat collecting partition wall, the theoretical calculation formula of the phase change temperature of the PCM was obtained, and it verified theoretically that the phase change temperature value should be 1 to 3 degrees Celsius higher than the target indoor air temperature. The evaluation index accumulated daily indoor temperature offset value was proposed for evaluating the effect of phase change materials on the indoor temperature of the passive solar house, and energy plus software was used to study the influence of the phase change temperature, the amount of material, and the thickness of the insulation layer on the indoor air temperature in a natural day. The results showed that there was a coupling relationship among the performance and between the thickness of the PCM layer and the This article was authored by Lei Cheng, Chunlong Zhuang, Shunbo Li, and others. We are article.tv, links in the description below.