Methods and systems for reroute and generation of backward routing information are provided. When an originator node wants to transmit a packet to a destination node and cannot transmit the packet to a next node recorded in a routing table, the originator node records a backward packet tag and information of the originator node into the packet, and transmits the edited packet to a backup node recorded in the routing table. The backup node retrieves a backward routing table in response to the backward packet tag to see whether a forwarding node corresponding to the originator node and the destination node is a backward routing terminal. If not, the backup node transmits the packet to the forwarding node. If so, the backup node removes the backward packet tag and the information of the originator node from the packet, and transmits the packet to the forwarding node.