Abstract: Aiming at the characteristic of fast attack from long distance for wire-guided torpedo,a method is presented which can quickly get the target motion factors based on grey relational analysis under an unmixed azimuth condition. According to proper division of initial target distance and velocity, as well as the board angles which are calculated via the variation of measured target bearing, different standard target classes are combined and different standard bearing sequences are obtained by simulation.Using the measured target bearing sequence as the refer sequence and the standard bearing sequences as the comparing sequences,the grey relational analysis is conducted to make sure that the target situation belongs to one of the standard classes, then the target motion factors are achieved. Simulation results show that the method can obtain the target motion factors with certain accuracy in a shorter time.