The invention relates to a wind power plant group automatic voltage control method based on load balancing. The method comprises the following steps that 1, an automatic voltage reactive power control AVC substation server of each wind power plant performs modeling analysis on the reactive power voltage regulation capability of the corresponding wind power plant, and analysis results are uploaded to a data central server A and a data central server B of a wind power plant group pooling station at the same time, wherein the two data central servers A and B are connected on the basis of a cross-data center two-layer technology OTV and a local load balancer. The method has the advantages that the wind power plants are modeled through the AVC substations of the corresponding wind power plants, the reactive power voltage regulation capability of the wind power plants is analyzed, the problem of detailed modeling in all wind power plants in an EMS system of a major network AVC control center is avoided, and the data maintenance amount of the major network AVC control center is decreased.