A XeCl excimer laser system used for treatment of vitiligo is developed. A push-pull pulsed switching power supply is designed for pulsed discharge of excimer lasers. The dependence of laser output energy on repetition rate, discharge voltage and gas lifetime is studied. The pulse-to-pulse stability is measured. Based on a feed-back control system, the discharge voltage is adjusted automatically to achieve laser operation at a preset energy level. The laser beam is transmitted through a liquid-core optical fiber to achieve a homogeneity of laser spot for treatment. The transmissivity of the 308 nm excimer laser in liquid-core optical fiber is about 70%. The repetition rate of the laser is 1~200 Hz. The discharge voltage can be adjusted from 18~25 kV. The pulse to pulse energy stability is less than 4%. The diameter of effective spot is 22 mm while the pulse output energy density is 2~3 mJ/cm2.