Abstract: A 100J level XeCl laser pumped by an intense relativistic electron beam -FLASH IT was constructed at Northwest Institute of Nuclear Technology. The cathode of diode for laser pumping is a 15cm x 60cm multi -point copper plate of graphite plate. The anode and pressure foils are both 25 micron Ti. The voltage of diode is measured to be 650-750kV and the current 290-350 kA. The pump power density ranges between 1.5-2.0MW/cm³. The aperture of laser cell is 20cm × 20cm and the effective excitation volume is 24 liters. We have obtained the laser output energy of 136J with a parallel-plane resonator and l.5mrad divergence angle from an unstable resonator. The laser power is measured to be more than 109W.