The thermophysical properties of phase change material include thermal conductivity, heat of absorption, and phase change temperature range. This paper investigates the measurement methods of thermophysical properties for phase change material inside a full-scale container. The influence of contact thermal resistance is considered in a thermal conductivity test, and the formula for calculating the thermal conductivity of a phase change material inside the full-scale container is derived. In addition, the heat of absorption is measured based on the calibration results of the correction coefficient for heat flux sensors. In order to verify the reliability of the measurement method, the thermophysical properties of docosane and erythritol inside a full-scale specimen are measured, and the results are compared with HotDisk analyzer results and published data. The comparison results reveal that the method proposed in this paper can accurately measure the thermophysical properties of phase change material inside a full-scale specimen.