Abstract: Low grade heat energy, such as solar radiation heat energy, is an important part of energy utilization and conversion. Due to the large amount and being not effectively used, it is emitted to the environment, resulting in waste and low energy efficiency. Phase change materials can absorb, store and release heat with its latent heat capacity, while their temperature fluctuation during phase changing is small. So combined the above two, the transformation of photo-thermal energy and heat storage based on phase change materials has become one of the important ways to utilize solar radiation energy. However, solid-liquid phase change materials are easy to leak. Therefore, in order to solve the problem of easy leakage of phase change materials, like polyethylene glycol, the waste biomass pomelo peel was focused, which was converted into a dual functional material of supporting skeleton and light absorption through a simple carbonization process, and further electro-deposition to enhance its light absorption performance. The shape stable phase change composites with the features of high loading capacity, high phase change enthalpy retention and excellent cycle stability were obtained by vacuum impregnation of polyethylene glycol. The maximum mass loss of 100 cycles is only 2.2%, and the heat storage efficiency of photo-thermal conversion is 87.5%. The shape stable phase change composites based on waste pomelo peel not only have low cost, simple preparation, but also realize waste utilization. The leakage free bio-based composites provide a new choice for further efficient and comprehensive utilization of low-grade heat energy.