A wireless sensor network gateway unit is proposed, which is designed for integration to a wireless sensor network (WSN) for providing a gateway function with a failed link auto-redirecting capability for the wireless sensor network. The proposed WSN gateway unit is characterized by the provision of an failed link auto-redirecting capability, which can respond to the failure of any sensor node in the WSN system by performing a failed link auto-redirecting operation for redirecting the down-linked good sensor nodes for linking to a nearby good sensor node to thereby allow the down-linked good sensor nodes to be nevertheless able to transfer data to the WSN gateway unit of the invention. This feature allows the WSN gateway unit of the invention to maintain good operational reliability for the WSN system.