An apparatus and method for an admission control for a service flow in a broadband wireless access communication system using a multi-hop relay scheme is provided. In a method for operating a relay station in a broadband wireless communication system using a multi-hope relay scheme, a request message requesting an admission control decision for a service flow is received from an upper node. It is determined whether a requested QoS parameter set included in the request message is supportable. If the requested QoS parameter set is supportable, the request message is forwarded to a subordinate relay station corresponding to a next hop in a data transmission path. If the requested QoS parameter set is unsupportable, a response message indicating the unsupportability of the requested QoS parameter set is transmitted to a base station.