After introducing the principal of the multi scale scratch analysis method of regional gravity data, this paper presents results of its application to Qinghai—Xizang (Tibet) Plateau, produces three sets of density disturbance, ridge coefficient and edge coefficient images. The density disturbance images can be used for delineation of hardness and rheological properties of continental tectonic units. The ridge coefficient images can be used for delineation of deformation belts, and the edge coefficient images can be applied for positioning the boundaries of structural division of the units. These images provide crustal geological and tectonic information from different aspects with depth information, are able to give quantitative constrains to any possible tectonic models. On the upper crust, these results are basically coincident with surface geological and tectonic mapping. They can also provide more structural information of the middle and lower crust that is usually difficult to be accurately inferred. For instance，the density disturbance images show the source zones and squeezed flows of the channel flows in the lower crust, as well as the position of subduction front of the Indian plate beneath the Himalaya mountain range. The ridge coefficient images provide positions of suture zones, deformation and subduction volcanic belts, ancient terrane collision belts and strike slip zones. Combination with the edge coefficient images one can draw out tectonic maps with different structural units in the middle and lower crust. For example, very high density terranes, the Kashmir and Chayu River, are divided from the Himalaya terrane, giving physical reasons for formation of the west and east structural knots in the India—Eurasia collisional belt. The multi scale scratch analysis provides not only plane geometry of structures and deformation belts, but also their depth extension and stereoscopic patterns. For instance，decrease of the low density volume from the lower crust to the upper shows possible diapiric intrusions of the low density channel flows.