A method for an end-to-end hybrid automatic repeat request and a system thereof are provided. The method is applicable in a cognitive radio network (CRN) including at least a source node and a destination node. There are paths between a source node and a destination node in the CRN, and each path has a plurality of wireless links. The method includes the following steps. The source node encodes information into a coded packet, divides the coded packet into coded sub-packets, and transmits the coded sub-packets to the paths. Through the wireless links of each path, a coded sub-packet is amplified and forwarded to the destination node. In addition, the destination node combines the coded sub-packets for decoding so as to recover the information, and transmits an acknowledgement packet to the source node for notifying whether the information is successfully recovered.