Aiming at the problems that the diesel generator set of the rail flash welding machine emits black smoke and pollutes the environment during welding,a high power energy storage type rail flash welding power source is developed. The power source has the characteristics of strong output capability,no harmful gas emissions,no noise,stable power supply,simple operation and quick start. It is suitable for mobile rail welding power supply requirements. The application of the power source can greatly improve the working environment of the operator and achieve zero pollution to the environment during the welding process.