Abstract: Achieving pulse compression and high energy is significant in the construction of an excimer laser angular multiplexing system. The laser pulse profile and energy extraction efficiency were studied changing the input seed intensity. An excimer laser amplification model was built based on four-level rate equations and excimer reaction kinetics. The amplification process was calculated and important parameters were numerically described, which were consistent with the experiment results. Moreover, the energy extraction efficiency of the amplifier was given under different input intensity by this model. The results show that about 95% of the amplified laser energy can be extracted when the laser pulse interval is 9.3 ns. Obviously, 9.3 ns laser pulse interval is a suitable choice for this excimer laser system.