In order to solve the problems of low cleaning rate and high breakage rate of the existing hop harvesting mechanical cutting devices, single factor and multi-factor orthogonal tests were carried out on hop stems of different varieties, such as Qingdao big flower, Marco Polo and Fragrant flower, by using the universal testing machine. The tests were focused on the influence of the factors, including moisture content, shearing mode and shearing velocity on shearing force. The results show that the influence of the above three factors are all significant, among which the first two are more significant. The shearing force will increase with the decrease of moisture content and it will decrease with the increase of shearing velocity. When the shearing velocity is kept between 100 mm/min and 200 mm/min, it will be the most advantageous to the cutting, and the slip cutting is the most labour-saving mode. The tests show that the cutting effect will be the best during the course of harvesting when the hop stems are fresh. The shearing velocity arrives at 100mm/min and the slip cutting mode is adopted. The results can provide a theoretical basis for improving the cutting devices of the existing hop harvesting machinery.