Abstract: Aiming at the problems of indiscriminate cutting of old and young tea leaves, crushing of tender buds, and mechanical damage to tea trees in the existing tea pickers, a tea-plucking device with automatic cutter adjustment was designed in this paper. Based on the terrain parameters of sloped tea plantations and the mechanical properties of tea stems, the mechanical and structural parameters of the harvesting device were determined, enabling flexible tea harvesting by the cutter. Through kinematic and dynamic analysis of the plucking device, the kinematic equations for horizontal cutter adjustment and dynamic equations for cutter cutting angle adjustment were established, identifying the main factors influencing cutter motion as the counterforce of the tea stem on the cutter, crank length, rocker arm length, and hinge mounting length. By using torque equilibrium principles, the necessary and sufficient conditions for longitudinal cutter deflection were obtained, determining the counterforce range as 0-55.42 N. Adams simulations of the horizontal cutter adjustment process were utilized to identify optimum crank length, rocker arm length, and hinge mounting length as 330 mm, 200 mm and 500 mm, respectively.