Abstract: There will be a lot of coverage holes in the random deployment Wireless Sensor Networks.The holes can be repaired by relocation of the redundant nodes and the first step is to find redundant nodes in the network.Now cluster mode is mainly used to find a suitable redundant node,but cluster mode with the way of flooding message consumes much time and energy.In order to improve the efficiency of the cluster mode,the network is divided into groups based on clustering and a group head node is elected in every group,the group head node is used to find a suitable redundant node.The simulation results show that the group mode outperforms cluster mode in terms of relocation time and total energy consumption.