Phase change Materials (PCMs) have a promising future in the energy fields of latent heat storage, solar energy conversion and building thermal management. In this work, two types of reduced graphene oxide (rGO) with different diameters were prepared and combined with paraffin, octadecanol and stearic acid PCMs, respectively. The one-pot hydrothermal method was employed for the synthesis of three-dimensional graphene network encapsulating organic PCMs. There is some research investigate that rGO addition has different degrees of impact on the latent heat and thermal conductivity of different kinds of organic PCMs. The rGO/PCM composite has a significantly enhanced thermal conductivity of 3.21 W m(-1) K-1 with an rGO loading of 10 wt%. Furthermore, a fraction of graphene was substituted by Ag nanoparticles. The thermal conductivity of rGO/PCM/Ag could be as high as 5.89 W m(-1) K-1. The size effect of rGO has a significant influence on the thermal contact resistance. The synergistic effect of rGO network and Ag nanoparticles also benefits the thermal conductivity of nano-enhanced phase change materials (NePCMs).