To achieve a cooperative navigation system for multiple autonomous underwater vehicles(AUVs)with three leaders,the localization performance evaluation function is derived without simplifying range measurement equation. In this way, the relationship among localization performance,formation configuration,cluster speed and distance between AUVs is analyzed. Theoretical analysis proves that the localization performance evaluation function can be degeneratedinto the simplest form under certain conditions,and the localization performance evaluation function in the simplest form is consistent with the corresponding results of theerror ellipse method and the Fisher information matrix method. Furthermore, Cramer-Rao lower bound based on localization estimation is derived to improve localization performance evaluation function, and the influence of rang measurement noise on the localization performance is analyzed. Finally, the optimal formation configuration, the suboptimal formation configuration and the worst formation configuration are constructed based on localization performance evaluation function analysis for the three-leaders cooperative navigation system, and the effectiveness of analysis and formation configuration is evaluated by simulation experiments. The results show that reducing cluster speed can improve the localization performance of system in the optimaland suboptimal formation configuration to a certain extent. Under the simulation conditions, the accuracy of localization can be increased by 9.11%. However, changing distance between AUVs has almost no effect on the localization performance. For a cooperative navigation systemin the worst formation configuration, reducing cluster speed and shortening distance between AUVs can both improve the localization performance. If they are both satisfied, the localization performance will be greatly improved. Under the simulation conditions,the accuracy of localization is increased by 63.17%,63.99%,and 81.50%,respectively.