Abstract: This work built a three-dimensional model of double-layer tree-shaped microchannel heat exchanger(MCHE),simulated and analyzed the heat-flow coupling field.The maximum temperature of single-layer MCHE was compared with double-layer MCHE,and the cooling efficiency of tree-shaped MCHE under parallel flow,contrary flow and cross flow was analyzed.When bottom heat fluxes q_w=50 W·cm^-2,The maximum temperature of single-layer MCHE is 102.5℃and double-layer MCHE is 63.38℃.The ratio of bottom temperature under 60℃is more than 60%.The cooling effect of double-layer MCHE is obviously better than single-layer MCHE,and the temperature distribution of heated surface is uniform,the temperature of the centre part is lower,which effectively solved the high temperature in the centre part due to the nonuniform heat dissipation.