In order to solve the problems of insufficient thermal stability and insufficient power capacity of the flexible base film bulk acoustic resonator, a new type of thin film bulk acoustic resonator based on flexible substrate is proposed in this paper. The silicon substrate of resonator has a certain number of embossments; the structure can effectively suppress the parasitic resonance mode, but also can reduce the device maximum steadystate temperature and maximum thermal stress. The simulation results of the finite element analysis software Comsol Multiphics show that the maximum steadystate temperature decreases by 4 ℃ for each additional embossment, and the maximum thermal stress decreases by 1×104 GPa. Compared with the conventional flexible substrate thin film bulk acoustic resonator, it has better thermal conductivity and thermal stress stability.