Abstract: The reduced scale experimental box was made based on the phase change wood-plastic component to study the thermal performance of the phase change wood-plastic envelope. During the experiment, the inside temperature was monitored and the thermal performance was tested by the method of radiant heat storage and convective heat release. Some conclusions were drawn that the phase change wood-plastic wall had more ideal room temperature adjustment ability compared with the normal woodplastic wall. Insufficient light had a great influence on the heat storage capacity of the wall, and the temperature control capability on cloudy days could be significantly reduced. The physical models and mathematical models of phase change heat transfer were built to improve the thermal performance of the phase change wood-plastic envelope, and the numerical simulation of the indoor air temperature, the convection heat transfer between the phase change interior walls and the indoor air, and the phase change interior wall surface temperature were performed using MATLAB.Resultsshow that both improving thermal conductivity and increasing the convective heat transfer coefficient can improve the thermal performance. Nighttime average indoor temperature can rise from 15.2 ℃ to 15.7 ℃ with the increase of the thermal conductivity, and the interior wall surface temperature and the convection heat transfer canalso rise; however, the rate of increase is small. Nighttime average indoor temperature can rise from 15.2℃ to 16.3 ℃ with the increase of the convective heat transfer intensity, the interior wall surface temperature and the convection heat transfer can also rise, and the rate of increase is larger; therefore, the latter has a greater potential for the improvement of the thermal performance.