Huhehu Depression is the main oil and gas rich fault zone in the eastern part of Hailar Basin. The 2nd Member of Nantun Formation coal bearing strata are an important exploration layer in Huhehu Depression. Further research on the sources and resource potential of coal and gas is of great significance for future oil and gas exploration. Through the evaluation of the geological and geochemical characteristics of coal bearing source rocks, a total of four sets of source rocks have been developed in Huhehu Depression. Among them, the 2nd Member of Nantun Formation develops coal bearing source rocks with high abundance, chitin group, and hydrogen rich vitrinite, while the 1st Member of Nantun Formation develops medium abundance source rocks with shallow lake facies. The trough area is in mature-highly mature stage, with Ro values ranging from 0.5% to 1.63%. Nantun Formation is the main source rock layer in the area; The acid hydrolysis experiments of different types of source rocks show that the methane ~ pentane carbon isotopes of coal gas are between coal seams and mudstones, and the coal gas in Huhehu depression is oil type gas. It is comprehensively judged that the coal gases in the 2nd Member of Nantun Formation of the area are contributed by the mudstones of the 1st Member and the 2nd Member of Nantun Formation, which are exogenous gases. Using the volume method, it is estimated that the geological resource of coal rock gas in the 2nd member of Nantun formation are 1.79 trillion cubic meters. The coal bearing source rocks have high hydrocarbon generation intensity, sufficient external gas, and a resource potential of over one trillion cubic meters. This is a new direction in the exploration breakthrough of eastern coal bearing faulted basins.