Abstract: At present, the main way of picking cucumber in greenhouse is hand-picking which has the problems of poor working environment and low degree of mechanization. It was oriented to mechanized picking and combined with the linkage structure of plane connecting rod and hinge spring, a pneumatic driven cucumber stalk shearing device was designed, and the dynamic simulation analysis of the device was carried out. In view of the influence of the parameters of cucumber stem shear device on the shearing effect, the actual data of different maturity of cucumber were measured and analyzed, and the shear test was carried out. The effects of maturity, cutting edge angle, cutting angle, bevel angle and other parameters on the shearing effect of cucumber stem were studied. The results showed that: in the middle stage of maturity（about two weeks after flowering）, cucumber stem was easier to be cut and the parameters of cucumber growth reached the peak at this time. However, in the late mature stage（flowering about three weeks）, the cutting force of cucumber stem stalk was large, so cucumber stem was harder to be cut. When the cutting edge angle was 8°～26° and the cutting angle and bevel angle were 0°, the air pressure required for cutting decreased gradually, the sliding cutting effect increased gradually, and the shear performance enhanced. When the cutting angle was 0°～45°, the cutting edge angle was 26° and the bevel angle was 0°, the air pressure required for shear increased with the increase of cutting angle. When the cutting angle was 0°, the required air pressure was lower than other angles, and the shearing effect was better. When the bevel angle was 0°～45°, the cutting edge angle was 26° and the cutting angle was 0°, the required air pressure first decreased and then increased, and the increase gradually increased. When the bevel angle was 15°, the shear force was lower than other bevel angle, and the shearing effect was better. According to the above results, it provided a basis for the selection of the time of picking cucumber and parameters of cucumber stem cutting device driven by pneumatic force.