A novel stearyl alcohol @ Co3O4/Expanded graphite composite phase change material (PCM) was prepared. Stearyl alcohol (SAL) and Co3O4/Expanded Graphite were selected as phase change material and supporting material, respectively. Expanded Graphite (EG), which was used to improve the thermal conductivity of PCM, was chemically modified using Co3O4. Co3O4 derived from ZIF-67 has abundant pore structure and large specific surface area. The structure of Co3O4/EG additive was characterized by SEM analyzing method. The prepared Co3O4/EG has the three-dimensional coupled network and hierarchical porous structure. Meanwhile, EG can effectively prevent the structural collapse and aggregation of Metal-Organic Framework (MOF) derivatives. The morphology and thermal properties of composite PCMs were analyzed with SEM, DSC and infrared imager. These results showed that the melting temperature of SAL@ Co3O4 /EG-8% composite phase change material was 51.25℃, and its latent heat was 191.63 kJ/kg. As the ratio of Co3O4 to EG increased from 1:1 to 1:8, the thermal conductivity of the composite phase change material SAL@Co3O4 /EG showed an increasing trend. When Co3O4: EG was 1:8, the thermal conductivity of PCM was about 47 times that of pure SAL(0.248 W/(m?K)).The infrared imaging results confirmed that the transient temperature variation of the composite phase change material sample was closely related to its thermal conductivity. All the test results showed that the new composite was a promising phase change material， because of its excellent thermal properties, it had a great potential application value in the field of heat storage.