In this paper,a GaN half-bridge power device packaging scheme based on high thermal conductivity graphite film is proposed to meet the requirements of the speed reg ulation accuracy, frequency and motion amplitude of the lidar rotating mirror scanning motor.The simulation results show that,compared with the three heat dissipation structures of FR-4 substrat e,FR-4 substrate with copper heat sink,and ceramic substrate,the GaN half-bridge power device using the FR-4 substrate with thermally conductive graphite film heat dissipation structure has the chara cteristics of low preparation cost,controllable process complexity,light weight of finished prod uct and good heat dissipation performance whose maximum temperature reduction is 32.6 ℃,and heat dissipation performance can be improved by 29.6%.Thermally conductive underfill acts as the rmal coupling and is indispensable in graphite film packaging structures.The heat transfer coeffi cient can affect the heat dissipation performance.When other heat dissipation influencing factors cannot be optimized,the heat dissipation effect can be improved by increasing the heat transfer coeffici ent.The research results in this paper have certain reference and guiding significance for the th ermal design of high frequency,high power density and small size power device packaging.