As the core equipment of the neutral beam injection heating system, the performance of arc power supply is very important. With the development and popularization of super capacitor technology, arc current power supply based on super capacitor has been widely used in many large-scale scientific devices. Pit circuit is an important component of arc current power supply. Its dynamic response characteristics and stability determine the performance of arc current power supply. A new current transfer circuit for arc current power supply is proposed in this paper, which can quickly fall and recover large current in 100 μs, and there is no overshoot in the fall and recovery process. The electronic switch for transfer (such as IGBT) has small overvoltage, high reliability and easy absorption circuit in the process of switching. The scheme is a good alternative to the traditional current pit circuit.