The invention provides a single-well drainage area quantitative calculation method based on a permeability preferential channel. The calculation method comprises the following steps of determining theoil and gas permeability preferential direction in a reservoir stratum; according to permeability parameters of all adjacent wells around a target well, determining target well permeability preferential channel; according to the target well accumulative output, back calculation and obtaining of oil supply areas under different extraction degrees; and converting the oil supply areas under the different extraction degrees to the permeability preferential channel of the target well, and obtaining the oil draining range of the target well under the different extraction degrees. The method has thebeneficial effects that the oil and gas field remaining oil enrichment region can be accurately positioned, the new well drilling success rate can be improved, the direct technical support is provided for oil and gas field benefit high yield, cost is reduced, benefits are increased, and the giant economic and social benefits can be generated.