A volcanogenic buried- hill hydrocarbon reservoir was firstly discovered by borehole FY- 2 in the Early Cretaceous Yixian Formation (K1y) of western margin from the north- central Fuxin basin. However, type of reservoir development and accumulation mechanism of hydrocarbon for volcanogenic rocks are still unclear in the Fuxin basin. Based on detailed analysis of petrology, seismic data, U- Pb dating, reservoir physical properties, and biomarker compounds, we reveal the accumulation mechanism of early Cretaceous volcanogenic reservoir in the K1y of the Fuxin basin. The volcanogenic rocks of the K1y can be divided into three types of volcaniclastic rocks (e. g. , volcanic breccia- tuff), volcanic lava (e. g. , basaltic andesite- basalt), and sedimentary pyroclastic rocks (e. g. , tuffaceous sandstone), which exhibit multiphase lithofacies sequences from intermediate- acid to intermediate- basalt. The forming age of intermediate- acid volcaniclastic rocks is about 124. 8 Ma by zircon U- Pb dating in the upper K1y. The volcanogenic buried- hill of the K1y is identified by a chaotic seismic reflection configuration, which reveals over 800 m thickness for buried- hill strata. The andesitic breccia from the K1y presents medium to good physical property of volcaniclastic reservoir, with thickness of 7. 25 m, porosity of 5. 36%, and permeability of 0. 026×10-3 μm2. The dissolution pores in volcanic cuttings are identified as the preponderant pore type of volcanic reservoir. Similar source of organic matter, water salinity, degradation degree and thermal maturity between volcanic crude oil of the K1y and source rocks of the early Cretaceous Lower Jiufotang Formation (K1jf1) are revealed by oil- source correlation of biomarker compounds. This indicates that the volcanic hydrocarbon of the K1y originated from adjacent lacustrine excellent source rocks of the K1jf1. We propose that the hydrocarbon accumulation of volcanogenic buried- hill in the K1y is mainly controlled by physical properties of volcanic reservoir improved by weathering and leaching and good spatial configuration of source rock- fault- reservoir- cap rock. Thus, an accumulation model of volcanogenic buried- hill reservoir was established in the K1y of the Fuxin basin.