The invention belongs to the nuclear power station electric energy metering system technical field, and specifically relates to a multi-unit nuclear power station generating capacity metering method comprising the following steps: 1, configuring an electrical energy metering system; 2, configuring an electric meter; 3, distributing the on-grid energy of each unit. The method can prevent the electric energy charging errors caused by different electricity price factors between the multi-unit nuclear power station debug units and commercial service units and between the commercial service units,thus reasonably distributing the on-grid energy of each unit.