This paper briefly presents the current situation of development of 3D gradient aeromagnetic (GAM) survey, and points out several problems to be solved by great efforts, such as basic installation and calculation techniques, consistency and attitude of magnetometer sensors and magnetometer compensation. It also proposes a specific scheme for large-scale or mid to large-scale 3D-GAM survey by introducing the regular tetrahedron measurement device and synchronized gyroscope data recording to the original aerial survey data.