A underwater laser localization method using cooperative targets was proposed to acquire the moving trajectories of underwater moving objectives to improve the tracking data precisely. By installing cooperative targets with total reflection characteristics on a measured objective, the angles and distances between the detection system and the objective could be measured by a pulselaser. The localization method and system structure for underwater detection were introduced and a digital model and measured results for the underwater laser localization were also given. Simulated results show that the proposed method is worth applying to engineering. According to engineering application, some practical problems about underwater laser localization to be solved were analyzed.