Abstract: In order to solve the problem of voltage violation in photovoltaic power distribution system, an optimal control method of distributed voltage regulator based on multi-agent is proposed. The characteristics of unbalanced distributed system and different types of voltage regulators were considered to ensure that the voltage deviation was minimized in a simple way without using a central controller. In addition, the possible changes in the distributed system topology were handled adaptively, and the robust control performance was guaranteed by the distributed multi-agent scheme. A simulation study was carried out using the node distribution test feeder. The results show that the proposed method can optimize and effectively manage the voltage regulator in the unbalanced distributed system even in the case of an agent fault, and reduce the total voltage deviation to the minimum.