A virtual square grid-based coverage algorithm (VSGCA) is proposed in this paper. Each sensor node divides its sensing range into virtual square grids, if all the grids are covered by neighbors, the target node is redundant node. Compared with some previous algorithms, VSGCA can guarantee the coverage and connectivity in the whole network and has a computational complexity of O(n×M), which is less than most of other algorithms. Simulation results show that VSGCA can achieve better performance with fewer active nodes and lower computational complexity.