As energy challenges continue to intensify, phase change technology emerges as an excellent solution for efficient heat storage. Biomass, with its renewable energy foundation and inherent biodegradability, offers significant potential for enhancing the performance and sustainability of phase change materials (PCMs). Nevertheless, the systematic review of the integration of PCMs and biomass remains scarce. Herein, the paper provides a comprehensive overview of the diverse applications of biomass in the PCM field, including its direct utilization in thermal management, role as encapsulation frameworks, and contribution to improving thermal conductivity. Moreover, the strong relationship between PCMs and biomass is emphasized, along with concrete prospects for the future implementation of bio-based composite PCMs. These efforts aim to stimulate widespread interdisciplinary research interest, seeking to provide insights for related studies and expand the multifunctionality of biomass materials in thermal energy capture.