Abstract: In order to improve the optical-optical conversion efficiency of the pulse amplification system model, the output characteristics of the dual-pass pulse amplification were studied by means of modeling and simulation. From the transmission characteristics, the relationship between output power and pump power, the relationship between output single pulse energy and pulse repetition frequency, and the relationship between conversion efficiency and repetition rate were obtained. The optical to optical conversion efficiency was 29.1% when the repetition frequency was 40kHz. Therefore, this dual-pass pulse amplification model improved the efficiency of energy conversion.