Because of the advantages of multi-parameter and the suppression of the shallow anomaly, the measurement of airborne magnetic gradient has become a new research hotspot in the field of airborne geophysical exploration in recent years. Based on AGS-863 three axis airborne magnetic gradiometer, it described the aeromagnetic gradient theory and the application research status. In order to summarize the relationship between aeromagnetic anomaly and the underground geological bodies, it designed some typical geomagnetic models, took a large number of forward simulation work, and drew the following conclusions: compared with the total field anomaly, gradient anomaly had more advantageous in the delineation of the magnetic bodies; for single magnetic body, the vertical gradient peak corresponded precisely to the center position of the magnetic body, and the longer of strike length of the magnetic body, the closer of the zero point of the main section to the abnormal body boundary, and the main section longitudinal gradient's maximum and minimum values exactly corresponded to abnormal body's left and right boundary and the main section's perpendicular section transverse gradient's minimum and maximum values exactly corresponded to abnormal body's up and down boundary; for the combined magnetic bodies, the range of the magnetic body which was locked with the main section longitudinal gradient peak and the main section's perpendicular section transverse gradient was enlarged, and the vertical gradient peak was shifted to the direction of the nearby magnetic body. By comparing the measured gradient data with the theoretical gradient data, it found that the measured gradient data has obvious advantages, and it can play a prominent role in the identification of human interference and high frequency geological information. These work could provide reference for the field data acquisition workers to understand and identify anomaly and distinguish between true and false anomaly, and provide some help for the anomaly interpretation workers.