Based on the data of rock coring, thin sections, physical properties and organic texture, the source reservoir characteristics and hydrocarbon generation potential of the Permian Lucaogou Formation migmatite in Malang sag, Santanghu Basin were analyzed by means of microscopic observation, rock pyrolysis analysis and geochemical parameter intersection, and the reservoir forming conditions were discussed. The results show that the reservoir lithology of Lucaogou Formation is divided into mudstone, argillaceous limestone, argillaceous dolomite and tuff. The reservoir space is mainly intergranular pore intergranular pore, intergranular pore, volcanic ash devitrification pore, felsic dissolution pore and dissolution fracture, and the physical properties are low porosity and ultra-low permeability. The dominant lithology of the source rock is dolomitic mudstone and mudstone, with an average total organic carbon (TOC) of 4.41%. The organic matter types are mainly type Ⅰ and type Ⅱ₂, and the maturity is mainly low maturity maturity. The source rock is characterized by high organic matter abundance, good organic matter type and hydrocarbon generation evolution in the oil generation stage. The comprehensive analysis shows that the shallow semi deep lacustrine mixed sedimentary rock source reservoir of Lucaogou Formation is integrated, with great hydrocarbon generation potential. It is a set of "self generation, self storage, high-efficiency accumulation and other source supply" tight dolomitic oil reservoir with favorable reservoir forming conditions of "good material foundation, sufficient basic conditions and efficient accumulation of oil and gas".