Abstract: PEG-zeolite solid-solid phase change material was synthesized by graft copolymerization. Polyethylene glycol(PEG) was used for phase change material and zeolite for skeleton. Infrared spectrometry (FT-IR), thermogravimetry analysis(TGA) and differentia scanning calorimetric(DSC) were used to study the microstructure, phase change behavior and thermal stability of PEG-zeolite solid-solid phase change material. Results show that PEG-zeolite solid-solid phase change material has different phase transition enthalpy and phase transition temperature by changing the molecular weight of PEG. The phase change enthalpy is up to 105.41 J/g. The thermostability is so good that the initial decomposition temperature is higher than 300 °C.