Abstract: In order to investigate the effects of stem processing on the physical properties of cut stems, the stem processing technologies including traditional technology (stem flattening + cutting), flattening twice before cutting and cutting twice without flattening on the length distribution, width distribution and other physical indexes of cut stems were studied with the image processing technology and the characteristic size distribution equation of cut tobacco. The results showed that:1) It was preferable to describe the size distribution of cut stems by way of characterizing the length and width of cut stems separately. The determination coefficients of length distribution and width distribution of the models were R² ≥ 0.982 9 and R² ≥ 0.993 7 respectively. 2) Comparing with the traditional technology, flattening twice reduced the characteristic width of cut stems from 1.54 mm to 1.21 mm, cut stems had better crimp form, but less shape uniformity and the width uniformity coefficient decreased from 2.99 to 2.70. Flattening twice affected cut stems' length slightly. 3) In the case of cutting twice, the shape of cut stem was obviously better though the yield of cut stem was lower. The characteristic width of cut stems reduced from 1.54 mm to 1.12 mm, while the width uniformity coefficient increased from 2.99 to 3.77; the characteristic length of cut stems reduced from 19.07 mm to 12.71 mm, and the length uniformity coefficient promoted slightly. The proportion of medium and short strands in cut stems increased from 37.58% to 83.47%.