A radio resource sharing method, wherein the method comprises: obtaining, by a network control device, a network parameter of a first communications system; configuring, by the network control device, a spectrum sharing manner between the first communications system and a second communications system according to the network parameter; and sending, by the network control device, a spectrum resource allocation message to a base station in the second communications system, wherein the spectrum resource allocation message comprises the determined spectrum sharing manner and information about a spectrum resource allocated to the second communications system; wherein the network parameter comprises at least one type of: distribution information of terminals with different capabilities in the first communications system or carrier quantity information of a base station in the first communications system; the distribution information of terminals with different capabilities comprises: a proportion or quantity of terminals in the first communications system that support carrier aggregation, distribution information of terminals in each cell that support carrier aggregation, a proportion or quantity of terminals that are in all terminals supporting carrier aggregation and that support cross-carrier scheduling, and distribution information of terminals in each cell that support cross-carrier scheduling; and the spectrum sharing manner comprises: a first sharing manner that does not support carrier aggregation, a second sharing manner that supports carrier aggregation, and a third sharing manner that supports both carrier aggregation and cross-carrier scheduling. obtaining, by a network control device, a network parameter of a first communications system; configuring, by the network control device, a spectrum sharing manner between the first communications system and a second communications system according to the network parameter; and sending, by the network control device, a spectrum resource allocation message to a base station in the second communications system, wherein the spectrum resource allocation message comprises the determined spectrum sharing manner and information about a spectrum resource allocated to the second communications system; wherein the network parameter comprises at least one type of: distribution information of terminals with different capabilities in the first communications system or carrier quantity information of a base station in the first communications system; the distribution information of terminals with different capabilities comprises: a proportion or quantity of terminals in the first communications system that support carrier aggregation, distribution information of terminals in each cell that support carrier aggregation, a proportion or quantity of terminals that are in all terminals supporting carrier aggregation and that support cross-carrier scheduling, and distribution information of terminals in each cell that support cross-carrier scheduling; and the spectrum sharing manner comprises: a first sharing manner that does not support carrier aggregation, a second sharing manner that supports carrier aggregation, and a third sharing manner that supports both carrier aggregation and cross-carrier scheduling.