The west and north sides of the Sichuan Basin are adjacent to the fold—thrusts, which are different in tectonic evolution and deformation characteristic. The Longmenshan thrust belt experienced two major periods of crustal horizontal shortening in the Late Triassic and Cenozoic, the south segment experienced major deformation in the Cenozoic and forms mid—high angle basement involved imbricate thrust structure, while the north segment experienced major deformation in the Late Triassic and forms low angle basement involved imbricate thrust structure. The Micangshan thrust belt experienced four major periods of thrust deformation in the Late Triassic, early stage of Middle Jurassic, Late Jurassic—Early Cretaceous and Cenozoic. Superposition structure is familiar in field. Lower and Middle Triassic is the detachment layer, basement involved thrust structure, back thrust structure and fault related fold are widely developed beneath the detachment layer, while these structures are rarely developed above the detachment layer. The Dabashan thrust belt experienced three major periods of thrust deformation in the Late Triassic, middle and late stage of Middle Jurassic and Cenozoic. The thrust belt is characterized by multi level detachment structure. The structure is brittle deformation in major changed to ductile deformation in major gradually from SW to NE.