The invention discloses a method for realizing real-time control of a power supply system by using an experimental-physics-and-industrial-control-system(EPICS)-based finite-state machine. The power supply system is composed of a plurality of power supplies that are distributed at different physical positions and are independent of each other. During the operation process of the power supply system, all power supplies are required to have certain time sequences and synchronization and can work according to given logic time sequences. According to the operating characteristics of the power supplies, an EPICS-based finite-state machine is employed and five states are defined, so that real-time control and ordered state conversion of operation of multiple power supplies are realized and thus the power supply system can carrying working and synchronization based the given time sequences. Therefore, the powerful guarantee is provided for the stable operation of the fusion supply and the operating requirement on the power supply system by the nuclear fusion device can be met.