The human-computer interaction optimization method was applied to solve the complicate multi-objective optimization design problem of vegetable seedling automatic pick-up mechanism. After the mechanism optimization mathematic model was established, the Visual Basic-based computer-aided analysis and optimization software was developed. The design variables’ impacts on the objectives and constraints were analyzed. The optimization combination of structural parameters meeting the seedling pick-up requirements was obtained. Then, the ADAMS software and high-speed digital video camera and image processing technique were used in simulation experiment and bench experiment for testing its kinematics characteristics. The basically consistency of experimental results and theoretical analysis results showed that the kinematics model and its optimization design theory and methods of the mechanism were correct and reliable. At last, it is proved through seedling pick-up experiment that the mechanism can successfully complete seedling pick-up operation with the success rate of 80%. 