On the basis of several geological facts, such as the continental basins are often rich in oil while the marine strata are lacking of significant oil fields, small inland basins contain rich oil and gas, and that oil and gas are associated with metallic-nonmetallic deposits, this paper suggests that a lateral oil-gas source may be responsible for the distribution and formation of oil and gas fields in the mainland of China. In the light of the CPMF model (model for collisional petrogenesis, metallogenesis and fluidization), the authors attempt to analyze the mechanism of the fluid generation and migration as well as fractionation and enrichment of its organic and anorganic components, and consequently, propose a model for fluidization and lateral oil-gas source during the transformation from basin to orogen. The objectivity and scientificity of this model are illustrated in four aspect-s, i.e. the intensive enrichment of metallogenic elements in the present oil-gas fields, the abundant discoveries of organic components such as hydrocarbons in ore fluids in the erogenic metallic ores, the production of oil and gas from the transformation of organic matter in sediments during the basin-orogen transformation, and the spatio-temporal coupling of oil-bearing basins and orogenic metallogenic provinces. Finally, laws in formation and distribution of the continental oil-gas fields in the mainland of China are discussed, and the direction for exploration of petroleum is pointed out.