Abstract: North Carnarvon basin is the main production in Australia petroleum basin, and it is also the one of main rich-gas basins. The Triassic strata are of big thickness and widely distributed, potential of nature gas resources are huge and the reservoir quality is good. The early Triassic, the entire northwest continental shelf for shallow sea covers. The basin deposits Locker shale. In the middle-late Triassic, the northwest continental shelf generally occurred regression retreat, the basin is the river delta facies in Mungaroo group, the lithologic features for thick layer of sandstone with thin layer of mudstone, and contain coal seam. The upper Triassic Mungaroo group is the main purpose of the exploration layer, it is also the main hydrocarbon source rocks of the development of the layer section, the reservoir and hydrocarbon source rock in a "sandwich" type, and sand development zone and the high quality hydrocarbon source rocks distribution are folded. Throughing the sedimentary characteristics and spatial distribution analysis of the organic matter in Mungaroo group, the rule of the Triassic organic matter space distribution has been made clear, and the Triassic terrestrial organic matter hydrocarbon source rocks of the development of the pattern has been put forward, for Australia North Carnarvon basin oil and gas geologic research and offshore oil and gas field development similarly in China provide geologic foundation.