A method of requesting and allocating an upstream bandwidth in an RS in a multi-hop relay BWA communication system is provided. The RS receives an upstream bandwidth request message including an upstream bandwidth from at least one MS for a predetermined time period, detects the requested upstream bandwidth from the upstream bandwidth request message, calculates a total requested upstream bandwidth by summing the requested upstream bandwidth from the at least one MS, generates a new upstream bandwidth request message including the total requested upstream bandwidth, and sends the new upstream bandwidth request message to a BS.