How to deploy multistatic sonar to achieve the maximum coverage of the monitoring area is an important issue in multistatic sonar application. Based on the bistatic detection model，the detection range of bistatic sonar is approximated as a Cassini oval，a multi-objective optimization model for the coverage problem of multistatic sonar is established，and the monitoring area is discretized into a deployable grid to refine the multi-objective optimization model of receiving nodes. Nondominated Sorting Genetic Algorithm II (NSGA2) is improved by removing the limitation of the number of nodes and increasing the reconfiguration operation of nodes. Simulation results show that the Improved NSGA2 (INSGA2) has faster convergence speed and better global search ability than the traditional NSGA2，and obtains a better Pareto front，which provide a reference for the optimal deployment of multistatic sonar.