To reveal the mechanical characteristics of BRT asphalt pavement structures under the combined effects of the temperature field and load of buses, a series of finite element analysis models were established in the software application ABAQUS to simulate the Lanzhou BRT asphalt pavement project. The actual BRT road temperature field in summer and loads of buses at different speeds were introduced in the model with user subroutines before conducting a sequentially coupled thermal-mechanical analysis. The results indicated that the BRT asphalt pavement structure readily experienced permanent deformation, mainly comprising unstable rutting during the high-temperature season, and the possibility of cracking was higher for the subbase bottom than for the base. Temperature imposed a greater influence than BRT vehicle frequency. To delay fatigue cracking of the base and subbase and the shear failure of asphalt pavement structures, BRT operating speed should be controlled within 30–40 km/h. In actual BRT asphalt pavement engineering, special attention should be given to the deformation resistance of the intermediate surface layer.