Phase change material composite with enhanced thermal conductivity were synthesized by sol-gel method using polyethylene glycol (PEG) as phase change material, 3-aminopropyl triethoxy grafted silicon dioxide (SiO2) as supporting material and oxide carbon nanotube(O-CNTs) as thermal conductivity reinforcer. The structure and morphology of PEG/APS-SiO2/O-CNTs composite were characterized by FTIR, SEM,XRD and DSC. When PEG content was 82.0%, the composite PCM still had good form-stable effect, and the enthalpy of melting and crystallization reached 134.2J/g and 126.6J/g. More importantly, the PEG/SAM composite retained good thermal properties after 500 melting and cooling cycles, the enthalpy decreased by only 3.3%. Compared with the PEG, the thermal conductivity enhancement rate of the composite with 0.6% O-CNTs was 28.1%，up to 0.41 W/(m?K). The infrared thermal imaging results show that the energy storage efficiency of the composite phase change materials is obviously improved.