The invention relates to a method for characterizing the lamina structure of a tobacco leaf. The method is characterized by comprising the following steps of: (1) sampling; (2) dispersing and paving materials; (3) collecting a lamia image; (4) measuring a lamina area; (5) calculating the area percentage of intervals; (6) calculating the accumulative area percentage; (7) fitting a distribution equation; (8) calculating a characteristic area; and (9) acquiring the lamina content of the intervals of any areas. The method has the advantages that: the distribution of lamina size is described by using the continuous distribution equation, the uniformity of the distribution of the lamina size and the integral size of the lamina are characterized by utilizing a uniformity coefficient b and the characteristic area x0.5, and simultaneously, the lamina content of the intervals of any areas can be acquired by the distribution equation of the lamina. The method overcomes the defects of the conventional method, and characterizes the structural distribution condition of the lamina comprehensively.