Nonuniform random distribution of sensor node or energy of some sensor nodes is exhausted caused by load imbalance may lead to coverage holes emerged in wireless sensor networks（WSNs）.Aiming at the detected coverage hole

based on tangent circle restorative algorithm is proposed to prove the feasibility of the algorithm in theory.The basic principle of the algorithm is to seek center location of tangent circle by two adjacent boundary nodes

namely location of the new mobile node

by iteratively solving center location of tangent circle to achieve the purpose of repairing.The simulation experiment shows that the algorithm not only can reach 90 % repair rate

but also the redundant is lower than other algorithm after repairing.