In this paper, the study on the mantle fluids, isotopic geochemical provinces, the distribution of low-velocity and high-conductive layers in mid-crust shows that: 1)the non typical sedimentary rocks as special reservoirs are products of metasomatism among mantle fluids enriched with alkali metals K, Na and alkaline earth metal Mg; 2)Sino-Mongolia block as the Pacific-type block has the giant petroleum resource potential; and 3)the low velocity-high conductive layer of mid-crust in the basin controls the distribution of oil-gas fields. Therefore, some of the oil and gas in Hailar-Tamtsag Basin might belong to the deep inorganic origin. some large oil and gas fields may be found in Budate Group buried hill belt.