Abstract: In order to solve the problems of high labor intensity and low labor efficiency in the manual harvesting of asparagus lettuce, the research group designed a single-row side-hanging lettuce harvester based on preliminary experiments. The article briefly describes the structure, working principle, and power selection of the lettuce harvester, as well as the structural design and theoretical analysis of each component. Taking the forward speed, blade rotation speed, and blade angle of lettuce harvester as the experiment factors, the orthogonal experiments were carried out to study the factors affecting the harvest quality of lettuce. The primary and secondary factors affecting the harvest loss rate, damage rate, and breaking rate of lettuce were determined as cutting speed, forward speed, and cutting angle. The optimal combination of parameters for the operation of the lettuce harvester was determined as a forward speed of 0.25 m/s, a cutting speed of 360 r/min, and a cutting angle of 6°. Under these conditions, the harvest loss rate, damage rate, and breakage rate of lettuce harvesting were less than or equal to 5%, meeting the requirements of mechanical operation quality.