Manipulation of elastic waves to achieve rainbow trapping effect has attracted wide attention. However, most of the current researches achieve rainbow trapping effect by changing the structural parameters, which means that the structure and mechanical properties are always fixed. Realizing the actively tunable working frequency range in elastic topological systems and obtain multi-dimensional rainbow trapping is still a challenge. In this paper, we design a topologically protected second-order thermostatic phononic crystal (PC) plate by using f...