In hot summer and warm winter climates, phase change materials (PCMs), with their ability to absorb and store thermal energy, can effectively reduce indoor temperature fluctuations and lower cooling loads when applied to roofs. Therefore, this study proposes a novel Radiative cooling-Dual phase change material (RC-DPCM) roof and conducts experimental research on its regulation of indoor and outdoor thermal environments. This energy-efficient roof integrates radiative sky cooling with PCM latent heat storage technologies within a compact building envelope. The innovative dual-PCM configuration can store heat from both indoor sources and outdoor solar radiation during the day through integrated PCM layers. At night, radiative cooling materials emit heat to the deep universe, helping the PCM layers complete solidification. The thermal performance of the RC-DPCM roof was tested in hot summer and warm winter climates compared to other roof designs: a single layer of aluminum (AL) roof, the Aluminum-Thermal insulation (AL-TH) roof, the Radiative cooling (RC) roof, the Radiative cooling-Outside phase change materials (RC-OPCM) roof, and the Radiative cooling-Inside phase change materials (RC-IPCM) roof. Results showed that the RC-DPCM roof significantly improved indoor thermal comfort and efficiency. Compared with the AL roof, the RC-DPCM roof reduced the average indoor temperature by 1.13 °C (or 2.49 °C during working hours) and continuously dissipated heat from the indoor environment to the ambient environment, reducing the cooling load. Additionally, the RC-DPCM roof achieved a 172.9 % average cooling load reduction during working hours, outperforming other roofs, thus demonstrating its potential as an innovative solution for sustainable and energy-efficient buildings. The RC-DPCM roof effectively reduced peak indoor temperatures and cooling load, demonstrating its potential as an innovative solution for sustainable and energy-efficient buildings.