During the period that the Photoconductive Semiconductor Switches(PCSS) is operating at a high repetition frequency, it generates filament current heating, then the temperature of the PCSS quickly exceeds the maximum operating temperature, causing the PCSS to fail or damage. Combining the advantages of microchannel heat sink and jet cooling technology, a high-efficiency micro-channel/jet impingement heat sink is designed. Through experimental tests, the heat transfer characteristics of the micro-channel/jet impingement heat sink under different operating conditions are studied, and the heat dissipation performance is compared with that of the honeycomb micro-channel heat sink imported from the United States. The experimental results show that when the volume flow rate is 3 L/min, the heat transfer coefficient of the micro-channel/jet impingement heat sink exceeds 35 000 W/(K·m2), and the heat dissipation is as high as 1 000 W, which is higher than that of the honeycomb microchannel heat sink by 45%. Under the test flow rate, with the increase of the volume flow rate, the average heat transfer coefficient of the micro-channel/jet impingement heat sink approaches a linear increase. The average heat transfer coefficient of the honeycomb micro-channel radiator increases slowly at large flow rates. In addition, compared with the method that cooled by the honeycomb microchannel heat sink, the uniformity of the heat source temperature cooled by the micro-channel/jet impingement heat sink is significantly better, and it can reduce the temperature fluctuation of the heat source surface by 58%, which is more conducive to reduce the thermal stress of the PCSS.