Objectives:In recent years, the Longmenshan fold—thrust belt is a natural laboratory for domestic and foreign experts and scholars to study complex geological structures. Through the field geological survey, fine seismic structure interpretation, the latest advanced imaging data are used, selecting three typical lines of the Longmenshan northern, middle and southern sections，which is basically vertical toward the strike. With the aid of Geosec 2D balanced crosssection technique, the tectonic development and evolution of the Longmenshan fold—thrust belt are analyzed. Through the deeply analysis of the tectonic development and the evolution history of faults, the author have summarized seven tectonic development style and tectonic feature patterns of the northern, middle and southern sections. Methods：This paper carries out research with seismic profile，geological outcrops and balanced crosssection comprehensive analysis and previous research results. Results:Through the indepth analysis of the tectonic development and the evolution history of faults, the authors have summarized 7 tectonic development patterns and tectonic features of the northern, middle and south sections. By comparing the tectonic development and evolution characteristics of the northern, middle and southern sections, it is confirmed that the Longmenshan fold—thrust belt is a multistage structure formed by superposition of multistage tectonic movements. The results show that the basement is involvedthrusting, Thrusting thrust, passive roof duplex and other structural styles. Before the early Indo—China movement, the stress environmental mainly was extensional environment, slowly uplifted; and lately was the compressional environment, rapid thrusting uplift and till the Himalayaorogeny period stereotype.  Conclusions: On the basis of constructed style analysis, combining the comprehensive evaluation of the petroleum geology and the structural characteristics of gas fields found in the nearby sections, the structural styles of the favorable oil and gas are predicted. The passive faultbend and faultpropagation folds, passive roof duplex, back thrusts are favorable structural styles of oil and gas exploration.