In order to improve the load capacity of the substrate in form-stable phase change materials (PCM), superporous hydrogels (SPH) were prepared by optimizing the process parameters by using a foam polymerization method using acrylic acid and acrylamide as monomers; and SPH was used as substrate, water was used as PCM and carbon nanomaterials〔graphene oxide (GO) and carbon nanotubes (CNTs)〕were used as additive to prepared two kinds of superporous hydrogel/carbon nano form-stable PCMs (GO-H2O/SPH and CNTs-H2O/SPH). The properties of SPH and form-stable PCMs were characterized. The results showed that the internal pore size of SPH prepared by the optimized process was 100~500μm, and the mass fraction to load PCM of it was up to 95.7%. The phase change enthalpy decreased from 352.3J/g of pure PCM to 337.1J/g of CNTs-H2O/SPH, which decreased by only 4.3%. However, the addition of SPH reduced the thermal conductivity of PCM by 42.1%. Adding GO and CNTs could increase the thermal conductivity and the rate of charging and discharging of form-stable PCMs. When the mass fraction of GO and CNTs was 0.2%, compared to the form-stable PCM without carbon nanomaterials, the thermal conductivity of form-stable PCMs was increased by 91.5% and 86.0% respectively. The form-stable PCMs also had good thermal cycle stability and could be recycled.