Satellite gravity field data and wavelet multi- scale analysis methods were used to image the three- dimensional density structure of the Africa Great Rift, and the density disturbance images on multiple depth- equivalent layers of the crust and upper mantle of the Valley were obtained, which provided important supporting evidence for the study of the lithospheric structure and Earth dynamics. The results show that the western rift branch of the middle section of the East African Rift Valley is homologous to the mantle- source melt of the eastern rift valley, but the western branch is not fully developed with later formed time. The kinetic mode of the Great Rift Valley is a tree- shaped bifurcation mode of melt- and- fluid upwelling, which includes: (1) low- density fluid swells up in a large area of the asthenosphere; (2) the melt- and- fluid continues to surge up in the lithosphere, partially converted into basic magma, and the plane area shrinks; (3) after entering the earth's crust, the upwelling molten fluid bifurcates into multiple branches, and the total plane area is further reduced; (4) the melt—fluid only moves in the rift zone after the upsurge to the upper crust, reflecting the volcanic chain and basalt belt.