Abstract: In order to save the heat of radar and other electronic equipment with high heat flux,a metal microchannel heat-sink with the aspect ratio of 5 and the hydraulic diameter of 166.67μm was designed by numerical simulation.Based on the breaking-up thermal boundary layer technology,the heat transfer performance of heat-sink was improved by interrupted microchannel.The microchannel baseplate was fabricated by UV lithography of SU-8 photoresist and micro electroforming technology.The metal microchannel heat-sink was obtained by welding the cover plate to the microchannel baseplate.A testing system for heat transfer performance was established.The microchannel heat-sink was experimentally investigated with deionized water as working medium.The experimental results indicate that the temperature at the bottom of heat-sink is lower than 40℃when the heat flux of heat source is 74.5 W/cm² and the flow rate of working medium is 1.8 L/min,and the average heat transfer coefficient of metal microchannel heat-sink reached 67.0 kW/(m²·K).