In order to solve the problem of node coverage suppression caused by blind area coverage and frequent data retransmissions in the pre-coverage process of wireless sensor networks, a coverage algorithm for wireless sensor networks based on reserve satisfaction model is proposed. Firstly, a new wireless sensor network node coverage model is designed, and the coverage index, coverage intensity, coverage balance evaluation coefficient and other evaluation dimensions are constructed to quickly evaluate the coverage quality of nodes. Secondly, the coverage equilibrium evaluation coefficient is calculated, and the backup model is adopted to optimize coverage quality and determine the backup working nodes with superior coverage performance. Then, based on the principle of coverage similarity, the coverage performance of working nodes is evaluated, and the first coverage evaluation method is designed. The statistical mean of coverage index is evaluated according to the moving path of the nodes. According to the sequence of the target nodes entering the coverage area, the working nodes with the best performance are activated. The simulation results show that the proposed scheme has higher network coverage, shorter coverage start-up time and less work compared with the current constant node coverage schemes of wireless sensor networks.