Shipboard dualaircraft cooperative locating becomes more and more important in modern antisubmarine war(ASW).In this papera proper method based on Euler equation and differential equation is proposed for computing the position of submarine and estimating the locating error for absolute locating and relative locating problems.It solves the error estimation problem well when two antisubmarine helicoptersthe lead and the wing planecooperate with each other for locating submarines.The processes for cooperative locating and its error calculation are presentedwhich is of great significance for ASW.