High- density methane inclusions were first discovered in Permian volcanic reservoirs in the Jianyang area of the western Sichuan Basin, providing new evidence for the genetic identification of volcanic gas reservoirs.Methods: This study utilized Raman spectroscopy to determine the density of methane inclusions. Subsequently, the reflectance of asphalt vitrinite was computed based on the results obtained from asphalt Raman spectroscopy. Furthermore, experiments were carried out to investigate the homogenization temperature in brine inclusions coexisting with hydrocarbons. Moreover, PVTsim simulations were employed to estimate the paleo- pressure of gas reservoirs in the Jianyang area.Results: The methane inclusions have a Raman shift peak ranging from 2909. 78 to 2912. 47 cm-1 and a density of 0. 21 to 0. 34 g/cm3, indicating their high- density characteristics. Furthermore, the reflectance of methane inclusions or pyrobitumen Raman vitrinite (RMVRo) ranges from 3. 32% to 3. 78%, indicating a high degree of thermal evolution. The methane inclusions also contain components such as C2H6, C3H8, CO2, and a significant amount of pyrobitumen distributed throughout the reservoir, suggesting a connection between the gas reservoir and the cracking of ancient oil reservoirs. The homogenization temperature of brine inclusions in hydrothermal minerals varies from 137 to 183°C, with an average of 165. 8°C. PVT simulation results show that the capture pressure of brine inclusions associated with hydrocarbons in quartz and calcite within the gas reservoir ranges from 85. 4 to 135. 6 MPa, corresponding to a formation pressure coefficient of 1. 9 to 2. 3. Conclusions: Methane contains C2H6, C3H8, CO2 and other components, with a significant amount of pyrobitumen distributed in the reservoir. This suggests that the gas reservoir is related to the cracking of the ancient reservoir. The homogenization temperature of the brine inclusions associated with methane ranges from 115 to 135. 6 MPa, with the corresponding formation pressure coefficient between 1. 9 and 2. 3, reflecting the abnormally high- pressure characteristics of the reservoir. The formation of high- density methane inclusions in volcanic gas reservoirs in the Jianyang area is linked to reservoir cracking caused by deep burial, and high- density pure methane inclusions serve as important evidence for the enrichment of cracking gas reservoirs. Furthermore, the integration of density, composition, and homogenization temperature of high- density methane inclusions can serve as indicator for evolution pathway of cracked gas reservoirs.