The 1Gt oil field's finding has solidified the Mahu oil Field's status, the largest conglomerate oil region in the world, and demonstrated the enormous exploration potential of conglomerate reservoirs. Optimizing and selecting the target interval during hydraulic fracturing is challenging due to the significant heterogeneity of the conglomerate reservoir. Based on issues encountered in the actual production of oil and gas from conglomerate reservoirs of the Baikouquan Formation (T1b), north slope of Mahu Depression, the composition of gravel was examined and analyzed in this paper. A novel classification approach is developed considering the structural and compositional features of the conglomerate reservoir in the T1b. Taking into account the grain size, supporting forms, cementation degree, and compositional properties, the conglomerate of the T1b is categorized into two groups and eight subcategories based on the core and test results. The conglomerates of T1b were initially divided into fan delta front and plain conglomerates according to the type of genesis. Fan delta front conglomerates were divided into four types: tuff, metamorphic rocks and magmatic rocks-dominated gravel-supported cobble-to-boulder lithofacies (A-1); tuff and magmatic rocks-dominated matrix-supported pebble-to-cobble lithofacies (A-2); tuff-dominated matrix-supported granule-to-pebble lithofacies (A-3); and tuff-dominated gravel-supported granule-to-pebble lithofacies (A-4). Fan delta plain conglomerates were divided into four types: tuff and magmatic rocks-dominated gravel-supported granule-to-pebble lithofacies (B-1); tuff and sedimentary rocks-dominated gravel-supported pebble-to-cobble lithofacies (B-2); tuff-dominated gravel-supported cobble-to-boulder lithofacies (B-3); tuff, magmatic rocks and sedimentary rocks-dominated matrix-supported pebble-to-cobble lithofacies (B-4). The sedimentary structure, bedding, lithofacies association, composition, grain size, and poroperm characteristics of the different conglomerate lithofacies are investigated. The favorable lithofacies types have been evaluated from both the geological and engineering perspectives. The insight of this paper is expected to provide some references for oil and gas exploration and development, as well as the selection of favorable lithofacies for hydraulic fracturing of conglomerate reservoirs.