Aiming at the problems such as insufficient ability to detect discharge state and hysteresis of output of existing wire-cut pulse power supply, a self-adjusting pulse power supply based on FPGA is developed. The power supply can accurately identify the discharge state of each processing pulse by high-speed A/D sampling. By adjusting the pulse output frequency in real time according to different discharge states, the harmful discharge state can be suppressed and the effective discharge pulse ratio can be improved. The experimental results show that the machining efficiency of the Connecting Rod Cutting machine is improved by using the self-tuning pulse power supply, compared with that by using the constant frequency pulse power supply. The pulse power supply promotes the development of the reciprocating wire cutting machine to high efficiency, energy saving and automation.