Abstract: Heat storage technology is the key to achieving efficient operation of solar heating systems. This study takes the double-layer phase change materials hybrid tank as the research object. Through numerical simulation and experimental research methods, the thermal storage characteristics of the tank are simulated, analyzed, and verified by the experimental results. The thermal characteristics of a single-layer, double-layer phase change materials hybrid tank is compared and analyzed, and the influence of the position of the double-layer phase change materials on the thermal storage characteristics of the hybrid tank is explored. According to the research findings, the double-layer phase change materials hybrid tank has better thermal stratification and increased heat storage capacity when compared to the single-layer phase change materials hybrid tank. The heat storage capacity of the hybrid tank made of double-layer phase change materials is 9.7% higher than that of the conventional water tank. When the double-layer phase change materials are far from the inlet and outlet, the melting time of the phase change materials are closer, which is more conducive to the thermal stratification of the heat storage tank.