Abstract: In recent years, with the rapid development of microelectronics technology, the heat dissipation demand of MMIC chip has increased to an unprecedented height. The thermal performance of the MMIC chip cannot be accurately represented by the thermal resistance. Simulation indicates that the thermal resistance of the MMIC chip is affected by the thermal conductivity of the chip carrier. In order to improve the thermal performance of the MMIC chip, the materials with high thermal conductivity should be used as the chip carrier.With its high thermal conductivity and high carrier mobility, diamond has the best hope of becoming the heat dissipation material for the next generation of MMIC chip.