In order to analyze the gas reservoirs and main controlling factor of the central canyon reservoir in Qongdongnan Basin deep water area, we use artesian well cores, cuttings, logging, natural gas data and two-dimensional, three-dimensional seismic data. The results showed that multi period turbidities sandstone accumulated in the middle of or under the canyon have good reservoir quality, and they are the high quality reservoir of the area. Lithological traps and structural stratigraphic traps developed in the canyon created an important place for natural gas. Yacheng Oligocene source rocks and semi-enclosed shallow mudstone have big potential for gas, and provide a rich hydrocarbon source. A diapir or micro fissure below the canyon is an important migration channel for deep natural gas. Altogether, the reservoir forming conditions of the central canyon is good, migration and trapping are key elements in the area of gas accumulation. Most traps stereotypes in Yingge Sea Pliocene sedimentary period form a reasonable configuration with the underlying Yacheng source rocks, therefore, natural gas accumulated late, the important discovery of gas field L1 /L2 and L3 are good example.