With the growth of energy demand and the depletion of fossil fuels, the need for new energy storage materials is urgent. Phase change materials (PCMs) play a key role in thermal energy storage and can effectively balance energy supply and demand. There is increasing interest in biological macromolecules derived from nature, which have good biocompatibility, non-toxicity, easy biodegradability and tunable mechanical properties. The integration of PCMs with biological macromolecules is highly promising as it combines the advantages of both to meet the requirements of eco-friendly energy solutions. This paper reviews the recent research on this topic, covering biomass source selection, the functionalization process, various phase change composites based on biological macromolecules and biomass, as well as biomass-derived PCMs. Furthermore, the paper explores their performance across various application domains, including degradable materials, solar energy storage and utilization, building energy conservation, multifunctional wearable devices, electromagnetic interference shielding, flame retardant materials, and thermally stimulated drug delivery. Finally, the paper outlines prospective avenues for future research.