Metallic foams, especially copper foams (CF), have been investigated to solve the problems of leaking and low thermal conductivity of phase change materials (PCMs), which helps to promote the application in solar thermal energy storage and thermal management. In this paper, the surface and pore structure of commercial CF was modified by in-situ formed copper nanowires and the introduction of flake graphite (FG). The copper nanowires and embedded FG not only provide greater capillary absorption force to prevent the leakage of liquid paraffin but also enhance the thermally conductive and photothermal conversion efficiency of the phase change composites. The thermal conductivity of the modified CF supported composite PCM reaches 4.1 W m−1 k−1, which is 1.6 times of the un-modified CF supported composite PCM and 20.5 times of paraffin. These results indicate the great application prospects in the fields of solar thermal energy storage and thermal management.