The low efficiency of collector structure design is the key factor leading to the improper flow distribution of microchannel radiator.In order to achieve uniform flow in multi-channel radiators,ANSYS-Fluent was used to numerically simulate the flow performance in microchannels under traditional and optimized collectors.The gas-liquid two-phase flow model was used to analyze the mass flow distribution in microchannels.The applicability of microchannel radiators of the two collectors in different flow states was compared.The results show that the growth of the traditional collector along the wall boundary layer and the distribution of high and low speed are the main reasons for the uneven flow distribution;when the inlet velocity is 0.5 m/s,the mass flow deviation of each branch pipe in the traditional collector is 32.2%,while that of the optimized collector is only 8.9%,and the flow uniformity of each branch pipe is increased by 72.36%;the pressure energy utilization efficiency of the radiator under the optimized collector is high,the high pressure area is large,and the end pressure is in the medium pressure area of 140 Pa to 260 Pa;in laminar flow and turbulent flow,the flow difference between each branch pipe in the optimized radiator can be controlled within ±15%,while the traditional structure is about ±40%,the optimized structure has stronger applicability.