Mannitol (Man) as a medium-temperature and high-enthalpy phase change material has promising applications, but issues such as leakage and poor heat transfer remain limiting factors. Well-designed porous carbon carriers will have an improved effect on the phase transition process of sugar alcohols. This study utilized graphene oxide (GO) as a support framework to disperse and promote the in-situ growth of ZIF, and through high-temperature calcination, constructed a high thermal conductivity network porous carbon carrier (PC), achieving the modulation of the thermal properties of mannitol shape-stable phase change material (PC/Man). The heat of absorption of PC/Man reached 185.3 J/g, and after heating to 180 °C, there was almost no leakage within 30 minutes, and the thermal conductivity was increased by 36.86 % compared to mannitol. To further verify the heat transfer effect in the application process, Fluent software was used to simulate the solidification process of the heat storage material in a tubular heat exchanger, analyzing the relationship between temperature and liquid phase rate with time. The calculated results, along with experimental analysis, confirmed the excellent thermal conductivity of PC/Man. The ss-PCM prepared in this study has the characteristics of rapid heat absorption and release, with a large heat storage capacity, showing promising applications in the medium-temperature field.