A retransmission method of a relay station, RS , in a wireless relay communication system, the method comprising: determining whether data received from an upper node contains an error; if the data contains the error, generating a message, wherein the message comprises unique identifier, ID, information corresponding to the RS and a negative acknowledgement, NACK, corresponding to the data provided from the upper node; and sending the message to the upper node at a time point that is not pre-appointed with the upper node, if the data does not contain the error, transmitting the data to a lower node; if a NACK and additional information informing which node sends the NACK and which data the NACK pertains to is received from the lower node, forwarding the NACK to the upper node; and when receiving scheduling information for a retransmission of the data, retransmitting the data to the lower node based on the scheduling information if the additional information indicates that the data is corrupted at the lower node, and forwarding the scheduling information to the lower node if the additional information indicates that the data is corrupted at another lower node. determining whether data received from an upper node contains an error; if the data contains the error, generating a message, wherein the message comprises unique identifier, ID, information corresponding to the RS and a negative acknowledgement, NACK, corresponding to the data provided from the upper node; and sending the message to the upper node at a time point that is not pre-appointed with the upper node, generating a message, wherein the message comprises unique identifier, ID, information corresponding to the RS and a negative acknowledgement, NACK, corresponding to the data provided from the upper node; and sending the message to the upper node at a time point that is not pre-appointed with the upper node, if the data does not contain the error, transmitting the data to a lower node; if a NACK and additional information informing which node sends the NACK and which data the NACK pertains to is received from the lower node, forwarding the NACK to the upper node; and when receiving scheduling information for a retransmission of the data, retransmitting the data to the lower node based on the scheduling information if the additional information indicates that the data is corrupted at the lower node, and forwarding the scheduling information to the lower node if the additional information indicates that the data is corrupted at another lower node. transmitting the data to a lower node; if a NACK and additional information informing which node sends the NACK and which data the NACK pertains to is received from the lower node, forwarding the NACK to the upper node; and when receiving scheduling information for a retransmission of the data, retransmitting the data to the lower node based on the scheduling information if the additional information indicates that the data is corrupted at the lower node, and forwarding the scheduling information to the lower node if the additional information indicates that the data is corrupted at another lower node. retransmitting the data to the lower node based on the scheduling information if the additional information indicates that the data is corrupted at the lower node, and forwarding the scheduling information to the lower node if the additional information indicates that the data is corrupted at another lower node. <EOS>