A 100 J level XeCl laser pumped by an intense relativistic electron beam — FLASH II was constructed at Northwest Institute of Nuclear Technology. in China. FLASH II is a low impedance REB accelerator. It consists of a 64 stage Marx generator, pulse forming line, field-distortion main switch, pulse transmission line, output lineand diode. The cathode of diode for laser pumping is a 15 × 60 cm long multi-point copper plate or graphite plane plate. The anode and pressure foils are both 25 micron Ti. The voltage of diode is measured to be 650–750 kv and the current 290–350 kA. The pump power density ranges between 1.5–2.0 MW/cm3. The aperture of laser cell is 20 × 20 cm and the effective excitation volume is 24 liters. We have obtained the laser output energy of I36 J with a parallel-plane resonator and 1.5 mrad divergence angle from an unstable resonator. The laser power is measured to be more than 109 W.