Abstract: Solar energy, as a renewable and environmentally friendly source, is regarded as a feasible alternative heat source. However, traditional phase change materials (PCMs) are unable to efficiently absorb and utilize solar energy due to leakage issues and low light-to-heat conversion efficiency. In this study, a modified poly(p-phenylene benzobisthiazole) fiber (MPBO)/polyimide (PI)/MXene hybrid aerogel was successfully prepared through directional freezing and vacuum impregnation techniques, and by impregnating with octacosane, a phase change composite material with stable morphology, low leakage rate, high enthalpy, and high light-to-heat conversion efficiency was fabricated. Thanks to the capillary action of the aerogel skeleton and the introduction of MXene, effective encapsulation of octacosane and high light-to-heat conversion efficiency were achieved. At a 30%wt MXene content, the leakage rate of the PI/30%MXene/MPBO@octacosane (PPM30Oc) composite aerogel material was only 4.22%, which was 17.3% higher than that of PI/MPBO@octacosane (PPM0Oc). Additionally, due to the plasmonic effect on the surface of MXene, the surface temperature of PPM30Oc could reach up to 89℃ after 1200 seconds of irradiation at a light intensity of 100 mW/cm², and it still demonstrated excellent light-to-heat conversion ability after 20 thermal cycles. Due to the highenthalpy of octacosane and the low leakage rate of the aerogel, PPM30Oc material has a high enthalpy of 260.17 J·g⁻¹ anda phase change enthalpy retention rate of 93.47%. When phase change materials undergo phase transitions, they can absorb or release heat to the environment, thereby regulating the environmental temperature. Moreover, by taking advantage of the latent heat characteristics of phase change materials, energy storage and utilization can be achieved, making them have great application potential in the field of building energy conservation. When a light intensity of 100 mW/cm² was applied, the internal temperature of the house covered with PPM30Oc increased by 15.2℃ compared to that without coverage, which significantly expanded the application potential of the material in temperature regulation.