The invention provides a method for calculating a gas drainage radius by considering a seepage mechanism of a tight gas reservoir. The method for calculating the gas drainage radius by considering the seepage mechanism of the tight gas reservoir comprises the steps of 1, fitting a relation curve chart of initial permeability and a pressure-sensitive coefficient through a physical simulation experiment; 2, obtaining a relationship between effective permeability and a starting pressure gradient through the physical simulation experiment; 3, determining the pressure-sensitive coefficient and the starting pressure gradient through the chart; 4, calculating the gas drainage radius by considering the starting gradient; and 5, calculating the gas drainage radius by considering a pressure-sensitive effect and the starting gradient. According to the method for calculating the gas drainage radius by considering the seepage mechanism of the tight gas reservoir, external dependency of Chinese energy is greatly reduced; Chinese energy structure adjustment is promoted; and the method has an important support effect for stable production of natural gas.