Abstract: The mini-channel combined with the serpentine flow channel is introduced to cool the high power digital T/R module with high heat flux in local area. The liquid cold plate with mini-channel is designed. And the structure of the mini-channel heat sink is optimized through simulation, which also validates the cooling performance of the liquid cold plate. The result shows that the cooling performance of the mini-channel liquid cold plate is better than that of the traditional one, which can guarantee the electronic elements to work in the allowed temperature. This thermal design method can be widely used in the cold plate with high heat flux in local area.