The Junggar Basin, as one of China's important oil and gas production areas, contains abundant petroleum reserves. However, research on the basin's lake basin evolution is relatively limited, particularly regarding the relationship between lake basin types and the distribution of reservoir-cap rock assemblage during the Permian to Triassic deposition.This study, based on sequence stratigraphy frameworks, integrates structural evolution and paleoclimatic characteristics to systematically analyze the control of lake basin types on sequence-stratigraphy-filling and the distribution of reservoir-cap rock assemblage in the Junggar Basin. The results show that the Permian-Triassic sequence in the northwestern margin of the Junggar Basin has been divided into three supersequence (SSQ1-SSQ3) and eight third-order sequences (SQ1-SQ8). SQ2 is subdivided into the rift initiation system tract, rift climax system tract, and post-rift system tract. SQ6 is subdivided into the falling-stage systems tract, the lowstand system tract, expansion system tract, and the highstand system tract. The deposition period of SQ2 characterizes a typical underfilled discharge (UF-D) lake basin, where high-quality reservoirs mainly develop in the rift climax system tract, characterized by conglomerates and sandstones with residual intergranular pores and dissolution pores, resulting in relatively high porosity. The source rocks exhibit high productivity, conditions of high anoxic preservation, and weak dilution. The distribution of the Fengcheng Formation's reservoirs and source rocks is controlled by fault activities accompanied by the input of hydrothermal fluids and arid conditions induced by the Late Paleozoic glaciation.During the SQ6 deposition period, a typical overfilled lake basin is represented, with high-quality reservoirs mainly developing in the forced regressive and lake expansion system tracts, primarily consisting of sandstones. Continuous lake wave reworking and intermittent exposure increased porosity. The primary source of hydrocarbons is the SQ5 source rock, characterized by high productivity, poor preservation conditions, and strong dilution. The distribution of the Baikouquan Formation's reservoirs is controlled by tectonic uplift during the late Hercynian orogeny, the arid paleoclimate conditions of the Permian-Triassic transition, and the subsequent continuous lake transgression. This study reveals the sedimentary evolution patterns of the Permian to Triassic strata in the northwestern Junggar Basin, particularly the sequence-stratigraphy-filling characteristics and reservoir-cap rock assemblage distribution controlled by lake basin types. The findings provide important references for the study of lake basins with similar structural and climatic settings and have significant implications for oil and gas exploration.