Abstract: In order to improve the performance of phase change heat exchanger, this paper designed a flat micro-heat pipe array thermal storage device which paraffin was used as the heat storage phase change material. The thermal homogeneity of flat-micro heat pipe array was analyzed by experiments, the paraffin temperature distribution within the heat storage device and the charging/discharging power of the thermal storage device, and the charging/discharging heat transfer process of the thermal storage device under different inlet temperatures and flow rates for the cold/hot heat transfer fluid (HTF) were studied by experiments. Experimental results show that the performance of the flat micro-heat pipe array is steady and efficient during charging/discharging process, and the average charging power and the average discharging power of thermal storage unit are approximately 662W and 764W under the experimental conditions which the cold/hot HTF is 2.0L/min,hot HTF temperature is 80℃ and cold HTF temperature is 20℃.