Provided is a wattless distribution method for multiple grid-connected photovoltaic inverter system, including three-layer wattless optimization control. The method comprises the steps of detecting voltage at point of common coupling of a power station in a real-time manner; controlling and obtaining the reactive value required for voltage maintenance; conducting reactive power optimization with the target of minimum internal station loss. The invention is advantageous in that reactive control cost is greatly reduced; accurate control of reactive output of the internal station can be realized,and system cost can be decreased.