The present invention provides a passive power grid wide-area generation control method and system. The method comprises the steps of: obtaining an active difference according to difference of activepower of all the sub stations and a preset planning curve, and performing distribution of the active difference according to controlled sub stations; calculating regulating variables of all the execution stations according to the distributed active difference of the sub stations and the regulating variables of all the execution stations in the sub stations; and calculating the active power regulating variable of each generator according to the regulating variables of the execution stations and the regulating variables of each generator in the execution stations, and controlling each generatorfor generation according to the active power regulating variables. The passive power grid wide-area generation control method and system regulate the power output of a wind power/photovoltaic power station transmitted by a flexible direct current power grid to achieve optimal operation so as to effectively inhibit the wind power and photovoltaic power generation minute-level fluctuation characteristics, reduce the regulation pressure of bundling pump storage power stations and achieve wide-area generation control of a passive power grid formed by new energy power stations.