The power source system of the BEPCII linac is designed to amplify the microwave signals generated by the microwave source, providing sufficient microwave power for the bunching units and accelerating structures. The BEPCII linac power source adopts klystrons equipped with pulse high-voltage modulators to amplify microwave power, with a total of 20 sets of power source systems. The BEPCII linac uses klystrons as microwave power amplification devices, combined with pulse high-voltage modulators, auxiliary power supply systems, etc., to form a power source system with mature technology, stable and reliable operation.