HEAT is a new concept of plasma thruster,having the advantages of high specific impulse,long life,electrodeless ablation and high reliability. It is suitable for long time flight missions in deep space exploration in the future. Fistly,the structure and working principle of the thruster are introduced,and the principle of lissajous acceleration mechanism is introduced. The electronic trajectory of HEAT is analyzed. A formula of calculating the thrust is derived using the drift diffusion model. When the ratio of the particle radius of gyration and thruster is a specific value,there is a maximum thrust. The results of the theoretical analysis provide guidance for the design of the thruster.