Abstract: Temperature rise and hot spot formation in photoconductive semiconductor switch(PCSS) chip caused by joule heating restrain the PCSS’s power, repetition rate and lifetime, thus active cooling technology is necessary. In the paper, a high efficiency silicon rectangular micro-channel cooler is designed and experimentally tested. The cooler has two sections, principal frame and cover, joined by Si-Si bonding. The former section has an array of micro-channels between the distributary groove and the conflux groove, and the latter is punched by semiconductor etching technology. With water as coolant, the heat flux, temperature uniformity and fluid pressure drop at different coolant volumetric flow rate and inlet temperature are tested. The experimental results indicate that the cooler has a hig