To address the issues of uneven dispersion and low coverage rates that arise from the random deployment of nodes in wireless sensor networks, an improved snake optimization algorithm for WSN coverage optimization is proposed. First, Circle mapping is utilized for population initialization to bolster the diversity of the population. Moreover, an adaptive spiral search algorithm is employed during the exploration phase of the snake to extend the search range. Then, the introduction of pheromones from the black widow algorithm mitigates the tendency of the snake’s exploitation phase to fall into local optima. Note that the use of a differential evolution strategy enhances the capability for optimization. Finally, by applying the improved snake optimization algorithm to the deployment of sensor nodes and using the coverage model of sensors, the maximum coverage rate is determined. Experiments indicate that the improved algorithm can effectively enhance the node coverage and expand the WSN coverage area to reduce the node energy consumption and extend network lifetime.