Abstract: In order to discuss non-Darcy characteristics of gas flow in low-permeability coal seam,based on coal body classification system and test method of starting pressure gradient in sandstone,starting pressure gradient in coal seam which have different coal structure was measured,the regression relationship between starting pressure gradient and coal structure was acquired,fast recognition of gas flow state in coal seam was realized.Research results show that coal structure can be acquired according to sampling or wall observation in coal mine firstly,GSI value of coal samples will be obtained by use of coal body classification system based on GSI,secondly starting pressure gradient can be tested in laboratory and the relationship between it and GSI will be acquired,then fast acquisition of starting pressure gradient and fast recognition of gas flow state in coal seam which have different coal structure will be realized