Diagenetic mineral genetic mechanisms fundamentally control on reservoir heterogeneity and hydrocarbon accumulation within the high-temperature and overpressured Upper Miocene Huangliu Formation sandstones in the eastern margin of the Yinggehai Basin. Integrated analyses of cast thin section microscopy, cathodoluminescence imaging, fluid inclusion homogenization temperature measurement, carbon-oxygen-strontium isotopes, and rare earth element reveal the material sources, temporal evolution, and genetic mechanisms of dominant diagenetic minerals in the study area. The results indicate that the main diagenetic minerals in the Huangliu Formation reservoirs of the study area comprise two generations of calcite cement, designated as Cal-Ⅰ and Cal-Ⅱ, and two generations of quartz cement, termed QzⅠ and QzⅡ. Two calcite cement generations (Cal-Ⅰ, Cal-Ⅱ) exhibit hydrothermal signatures, including anomalously high fluid inclusion homogenization temperatures, LREE-enriched patterns, and Yb/Ca-Yb/La cross-plot clustering within the hydrothermal field, confirming sustained hydrothermal control on their precipitation. The Cal-Ⅰ exhibits dull-yellow cathodoluminescenc. During late-stage deposition of the Huangliu Formation, fault-driven migration of organic CO? origniates from organic acid decarboxylation within Sanya Formation source rocks provided the material source for Cal-Ⅰ. Cal-Ⅱ cement exhibits bright-yellow cathodoluminescence. During the late Yinggehai sedimentation, diapiric thermal baking decomposed carbonate minerals in Sanya Formation source rocks, producing abundant inorganic CO2. This combined with organic CO2 from organic acid decarboxylation in Meishan Formation source rocks, and both migrated into reservoirs, jointly supplying material sources for Cal-Ⅱ. The silica cement is predominantly composed of quartz overgrowths exhibiting black cathodoluminescence, designated as QzⅡ, with subordinate occurrence of brown-luminescing quartz overgrowths termed QzⅠ. Since 3 Ma, parts of the Huangliu Formation have been buried to depths exceeding 2500 m, experiencing intense compaction that led to significant pressure dissolution of quartz grains. The silicon derived from this pressure dissolution provided the material source for QzⅡ. On Al-Li, Al-Rb, Al-Cd, and Al-Ge bivariate diagrams, data points from QzⅡ and detrital quartz grains cluster within the same region, reflecting a homologous origin.