The reliability of wireless sensor networks is affected by faults that may occur due to various reasons. In ZigBee sensor networks, ZigBee specification presents a self-healing process which relies on its tree topology. When a ZigBee node failed, all of the descendants of the fault node should rejoin the network. Instead, we present an efficient scheme for repair itself after node failure that just one or some of the descendants should rejoin the network. It allows a subnet of fault node rejoin the network with minimum message exchanges and, therefore, saves energy. Simulation results show that most of subnet rejoin the network in the first level of sub-tree, and confirm the efficiency of the proposed scheme.