For the improvement of welding performance, high-efficiency inverter system was designed and applied that system to the conventional large scale Flashbutt welder. The inverter systems are consists of full bridge PWM power control system and DSP controller. This inverter system has increased switching frequency of power control system of Flashbutt welder. For the test of application effects, we compared an our inverter control system with a conventional thyristor control system. In the results, we confirmed that our system has decreased the welding spatter amouts and improved welding performance.