Abstract: In order to monitor and control tobacco lamina quality in threshing, image analysis method was used to measure tobacco lamina area. The fractal model of area distribution of tobacco strips was established based on the fractal theory, and fractal dimension was used to describe the characteristic of area distribution of tobacco strips. The results showed that the model predictions and measured values of area distribution of tobacco strip have high correlation coefficient. Fractal model can describe accurately area distribution of tobacco strip. Fractal dimension could describe the uniformity of tobacco strip structure. For tobacco leafs of different class, the fractal dimension could reflect tobacco characteristic difference in threshing. There is a liner relation between fractal dimension and percentage of >161.29 mm2 lamina, and the correlation coefficient was greater than 0.90. The determining method for tobacco lamina structure based on image analysis and fractal model could monitor and control tobacco lamina quality on line during threshing process.