To study the thermal environment of the room which is enveloped by the phase-change concrete composite wall with night mechanical ventilation,the dynamitic heat transfer mathematical physics model of the phase-change concrete composite wall with night mechanical ventilation and thermal balance model of the room are given based on enthalpy method.The dynamic heat transfer performance and indoor thermal environment are simulated in summer and the transitional seasons when the phase-change composite walls are applied in Beijing.The influencing factors of the phase-change composite wall,such as phase-change temperature,phase-change layer thickness,ventilation rate,ventilation time,and the locations of phase-change layer and the insulation layer are analyzed.The optimal results are as follows: phase-change layer should be as the inner layer,phase-change temperature is 26 ℃,phase-change layer thickness is 25 mm,ventilation time is 4:00 am to 6:00 am,and ventilation rate is 25 ach/h.