The invention relates to a power supply capacity and power grid load-based automatic control method of a virtual power plant. With the method adopted, defects in the prior art can be eliminated. According to the technical schemes of the invention, the virtual power plant includes power generation units, power consumption units, a dispatching center station and a local data acquisition device; the local data acquisition device is in communication connection with the power consumption units and the power generation units; the local data acquisition device is in communication connection with the dispatching center station; the power generation units and the power consumption units are both connected with a power grid through controllable interfaces; and the controllable interfaces are connected with the dispatching center station. The method is characterized in that the dispatching center station is provided with an environmental data module; and the dispatching center station predicts the overall power generation data of a target date according to stored environment data over the past years and the power generation data of power generation units which are connected into the power grid over the past years; and the dispatching center station selects power generation units and power consumption units which are to be connected into the power grid.