Abstract: By the modification of the AS350-B3 helicopter, the airborne gravity and magnetic measurement system suitable for the medium-low mountainous area is integrated. The 3D measurement network with the maximum slope of 3° was designed, and the gravity and magnetic measurement method by helicopter was first applied in the medium-low mountainous area. The measurement results show that the slow rise and fall measurement method can keep the aircraft track well in the three-dimensional space, and can effectively control the height difference between the intersection points of the survey line and the cross line, so that the survey line and the cut line form a network, which plays a beneficial role in the magnetic field leveling. The comparison of the results of the horizontal flight measurement and the slow rise and fall measurement shows that the slow rise and fall measurement method can not only take into account both gravity and magnetic measurement methods, but also exert more obvious mapping effect than the horizontal flight anomaly characteristics.