Abstract: The study device is the latent heat storage(LHS)tank which is developed by our research group and is of phase change temperature 80℃.A mathematic model is set up for heat transfer analysis.The research group investigates the effect rules of thermal perform parameter and geometry size of phase change material(PCM)which is the heat storage body,the bulk ratio of PCM to LHS tank and velocity of water which is the heat transfer fluid(HTF)on heat charge and discharge performance of the LHS tank by means of numerical simulation.The analytic result shows that when the thickness of the form-stable flat-plate PCM is about 8mm,the thermal conductivity is about 0.4W/(m·K),the bulk ratio of PCM to LHS tank is 65%~75%,and the velocity of heat transfer fluid is 0.005~0.008m/s,the heat charge and discharge rate of LHS tank is higher.