A communication method of a mobile station through a relay and a communication method of a relay system are disclosed. The communication method of a mobile station through a relay station comprises adding candidate relay information to channel status information periodically transmitted to a base station if a downlink signal quality value between the mobile station and the base station is less than a threshold value and a downlink signal quality value between at least one candidate relay station and the mobile station is higher than the downlink signal quality value between the mobile station and the base station; receiving information of a relay station selected among the at least one candidate relay station by the base station in accordance with the candidate relay information from the base station through a relay path indicator; and receiving data from the selected relay station at a time when the relay path indicator indicates. It is advantageous in that service delay of the mobile station is minimized and resources are efficiently used as the mobile station requests relay through the relay station in accordance with the channel status.