Abstract: In order to reduce the labor intensity of litchi harvest, combinating the characteristics of litchi fruit distribution and fresh-keeping, litchi picking mechanism was studied, and designed rotary scissor style litchi picking machine was designed. The structural optimization of the cutting blade was done based on the overall structural design of the picking machine. With the cutting force analysis of cutting blades during picking process, the results indicated that the moment installed block passing to cutting blade was 238.75 N, the reaction force of which the branche bringed on the cutting blade was 3 851 N, and the maximum cutting stress was 23.02 Mpa during the cutting process. The safety factor of the cutting blade was 8.99. Analysis results confirmed reliability of structural design of cutting blades and feasibility of picking mechanism which provided a basis for the further optimization of its structure and study of the picking mechanism.