【Objective】To design a rotary drum combing type litchi picker and optimize structures of picking parts. 【Method】 The four-factor and three-level orthogonal experiment was conducted, using the amount of tooth profile plate, the bend angle of tooth profile plate, the amount of blade and the drum rotation speed as influencing factors, and productivity, picking rate and crushing rate as picking indexes. 【Result and conclusion】 The optimal parameter combination was 4 for the amount of tooth profile plate, 120° for the bend angle of tooth profile plate, 13 for the amount of blade and 44 r·min^-1 for the drum rotation speed The productivity reached 2.604 kg·min^-1 based on the optimal parameter combination. The results provide reference for design and development of litchi picking machine.