Objectives: The Indosinian orogeny corresponds to the closure of the Palaeotethys between the South China, the North China, and the Qiangtang blocks in the Middle—Late Triassic, which produces wide tectonic and sedimentary events in the Longmen Mts. and its Sichuan foreland basin. However, this important orogeny was widely superimposed by the later similar northwest—southeast compressonal deformation corresponding to the collision between the Indian and Eurasian plates, which makes it difficult to identify the profound influences of the old tectonic activities on the initial tectonic and geomorphological features as well as the Cenozoic activities of the Longmen Mts. thrust belt. Studies focusing on the other boundary faults demonstrate that the truth of the formation history of the orogenic belt can only be approached through multiple techniques. In this paper, some major progress in Indosinian orogenic studies of the Longmen Mts. thrust belt and its foreland basin are introduced, which include the formation of the main faults, early thrust—nappe, klippen, as well as sediments and heat flow distribution in the Sichuan foreland basin, in order to further understand the formation and evolution mechanisms of the tectonic framework of the Longmen Mts. thrust belt. Methods: In recent years, studies on deep seismicreflection profile, dating of main fault and klippens, sedimentary sequence and sedimentation of foreland basin provide new perspective allowing study of the initial Indosinian tectonic evolution of the Longmen Mts. Results: The deep seismic reflection profiles and recent dating results reveal that large thrust—nappe occurred in the Longmen Mts. area, which resulted in the formation of the three main fault belts during Indosinian orogeny, and the emplacement of several allochthons in front of Longmen Mts. during postorogeny. Meanwhile, the large thrust—nappe caused large amount of sediments flowing into the Sichuan foreland basin. In addition, the strong faulting triggered the occurrences of large earthquakes. As a result, softsediment deformation structures began to develop in unconsolidated sediments.  Conclusions: We prefer that the detachment of a block of lithosphere caused the incursion of hot asthenosphere, which finally corresponded to the contraction in the Longmen Mts. fault belt and the elevated heat flow in the eastern margin of Tibetan Plateau. This early tectonic framework then strongly influenced the tectonic and geomorphic evolution of the Longmen Mts. fault belt during Cenozoic.