A beacon scheduling method of a router by a coordinator in a network system that includes the coordinator and at least one router, includes receiving an allocation request signal of a time period in which a beacon of the router is transmitted; determining the time period to be allocated to the router based on information relating to a time period allocation state; and transmitting information relating to the determined time period to the router. The beacon slots can be efficiently allocated and managed when the ZR joins or leaves the network. Therefore, it is possible to effectively prevent the beacon collisions between ZRs over the network.