The collisional orogenic belt composed of Songpan—Garze(Ganzi), Chuandian(Sichuan—Yunnan) and Yangtze blocks is an important part of the Tethys tectonic domain in China. The tectonic domain is affected by the strong tectonic activities such as the continent—continent collision between Eurasian plate and Indian plate, plateau uplifting, block cracking or splicing compression, and has recorded and preserved rich and comprehensive historical traces of Tethys tectonic activities. Meanwhile, it is one of the regions with the strongest crustal deformation in southwest China. What the relationship and constraint mechanism between the characteristics of superficial deformation and deep structure is a research hotspot in Earth science. Methods: To investigate the deep dynamic mechanism, crustal deformation and earthquake generation in the Tethys tectonic domain of China, we applied a joint tomographic inversion method for a large number of local and teleseismic data to have determined the 3- D seismic velocity and Poisson’s ratio models in the crust and upper mantle. Results: Based on the author’s continuous geology—geophysics studies for more than ten years, a low- velocity and high Poisson’s ratio belt is observed along the Eastern margin of Xizang(Tibet). This anomalous belt meets together with the hot upwelling asthenospheric materials to form an upwelling channel upwards to the upper crust. At the same time, a sharp contrast anomaly of multiple parameters on two sides of the Longmenshan (Longmem Mountains) fault zone is revealed in the lower crust and uppermost mantle. A distinguish overlapping zone of low speed (high Poisson’s ratio) and high speed (low Poisson’s ratio) has been revealed in the middle—lower crust under the Longmenshan fault zone. These imaged deep structural anomalies have a good consistency with the spatial distributions of basin pattern of depression and uplifting, surface stress and crustal deformation. Based on these obtained deep structural characteristics, a deep contact model across the Eastern margin of Xizang(Tibet) together with corresponding basin—mountain coupling relationship is proposed by comprehensive comparative analyzing of multi- parameter structure imaging, crustal deformation and seismogenic mechanism of large earthquakes as well. The constraint mechanism of the deep dynamic process of plate colliding and coupling on severe crustal deformation and generation mechanism of large earthquakes is clarified. Conclusions: The results of our model could provide some reference information for further understanding of the deep dynamic mechanisms on the plateau sharp uplifting, basin basement structure, basin pattern of depression and uplifting, as well as strong crustal deformation.