A series of a novel shape-stabilized phase change material of poly(hexadecyl acrylate)/graphene oxide (PHDA/GO) nanocomposite was fabricated by in situ free radical polymerization. The fabricated PHDA/GO nanocomposites mainly contain a poly(hexadecyl acrylate)-grated-graphene oxide (PHDA-g-GO) solid solid phase change material (SSPCM) and a PHDA solid-liquid phase change material (SLPCM). The PHDA-g-GO SSPCM plays two roles in the PHDA/GO nanocomposites: as the supporting material and as a phase change working substance. The effects of GO loading on the crystalline properties and the phase change properties of the PHDA/GO nanocomposites were investigated. The results indicate that the grain size of the PHDA/GO nanocomposites increases with GO loading. The nanocomposites have high thermal enthalpies, and their enthalpy efficiencies are significantly higher than those of traditional shape stabilized PCMs (TPCMs) because of the synergistic phase change effect of PHDA-g-GO and PHDA. The number of crystalline CH2 groups, including the terminal methyl, in the alkyl side chain of PHDA increases from 6.42 to 8.82. Moreover, the FTIR spectra and DSC curves of the PHDA/GO nanocomposites after thermal cycles are nearly the same as those of the original specimens, which indicate that the nanocomposites have excellent thermal reliability and reusability. This study not only provides a kind of novel shape-stabilized PCM with a high performance but also proposes a new way to solve the problem of enthalpy decline observed in TPCMs. (C) 2017 Published by Elsevier Ltd.