When designing and deploying wireless sensor network (WSN), sensor node deployment is one of the crucial issues for WSN providing high quality of service. Sensor node deployment could also affect network coverage, network connectivity, network lifetime, and energy consumption. This paper attempts to solve sensor node deployment problem in WSN. A mathematical model is constructed by considering coverage maximization, deployment strategy and other constraints. As the problem is non-deterministic polynomial (NP) complete, a new method called sparrow search algorithm (SSA) is used. A novel population structure is proposed to improve SSA to solve the problem. Two populations with central symmetry property are created in initialization. Crossover operator is used to exchange information of the two populations. The computational complexity of the improved SSA algorithm is also discussed. Numerical simulations are performed to solve the deployment problem in WSN. The improved SSA algorithm is tested and compared with other algorithms. The results show that the proposed method is useful to address NP complete sensor node deployment problem in WSN.