Cool coatings are typically used to address high-temperature problems with asphalt pavements, such as rutting. However, research on the effect of the coating structure on the cooling performance remains a major challenge. In this paper, we used a three-layer cool coating (TLCC) to experimentally investigate the effects of the reflective layer, the emissive layer, and the thermal insulation layer on the cooling effect using a self-developed cooling effect evaluation device (CEED). Based on the test results, we further established temperature fields inside uncoated and coated samples, which were used to study how the TLCC affects the inner temperature field. Our results showed that the reflective layer was the main parameter influencing the cooling effect (8.18 °C), while the other two layers were secondary factors that further improved the cooling effect to 13.25 °C. A comparison of the temperature fields showed that the TLCC could effectively change the internal temperature field compared with the uncoated sample, for example, by reducing the maximum temperature inside, whose corresponding position was also deeper. As the depth increased, the cooling effect of the TLCC first increased and then decreased slowly. The results emphasize the importance of considering the effect of the coating structure on the cooling performance. This study provides a reference for effectively alleviating high-temperature distresses on asphalt pavement, which is conducive to the sustainable development of pavements.