Provided are a method and system for providing a multicast service in a next-generation network (NGN), which can improve the quality-of-service (QoS) of broadcast services by separating a routing path calculation function and a resource allocation function during the setting of a multicast broadcast channel and enabling a resource control server to perform centralized resource control. In the method and system for providing a multicast service in an NGN, a multicast router calculates a routing path, and a number of multicast routers on the calculated routing path issue a request for resources for a desired multimedia broadcast channel, and a resource control server allocates resources to the multicast routers on the calculated routing path.