In this work, a unique electrically conductive polyethylene glycol (PEG)/carbon black (CB) shape-stable phase change composite (SSPCC) for peak load regulating of electric power system was prepared via a vacuum impregnation approach. Scanning electron microscope (SEM), differential scanning calorimeter (DSC) and X-ray diffraction (XRD) were used to study the micro morphology, crystallization behavior, crystallization structure and thermal properties. Leakage test and DSC results showed that when the PEG content in PEG/CB SSPCC was as high as 86 wt%, the phase change enthalpy and relative enthalpy efficiency were up to 147.7 J/g and 95.1 %, respectively. Fourier transform infrared (FITR) and XRD showed no chemical reaction between CB and PEG. Thermal cycling test showed that the PEG/CB SSPCC had excellent thermal stability and thermal reliability. Moreover, the good electro-to-thermal conversion ability of PEG/CB SSPCC (0.2 S/m) provided rich possibilities for peak load regulating of electric power system and corresponding thermal energy storage.