Abstract:To counter the threat of aeronautic magnetic detection , submarines can launch devices ( magnetic decoy) that cansimulate the aerial magnetic field characteristics , and hence the simulation requirements need to be analyzed in the process of stud-ying magnetic decoy. Aiming at this question, on the basis of analyzing the working principle, advantages and disadvantages ofcommonly used magnetic detectors, this paper establishes an aeronautic magnetic antisubmarine detection models based on scalarmagnetic detectors. Based on the estalished model, simulation requirements of magnetic source for counteriny magnetic detection areanalyzed, and the method and indexes of evaluating the countermeasure effectiveness which contain magnetic field power ratio, ad-justable index of magnetic field direction and effective area index are given, which provides a foundation for the research on themethod of simulating submarine' S aerial magnetic field.