Abstract: To provide a scientific design method for the bottom cantilever folding manipulator box of CNC grinding machine to optimize its human-machine interaction performance and improve the operation comfort and work efficiency of machine operators, the preliminary design of the manipulator box is carried out under the specification of ergonomics. The RULA (rapid upper limb assessment) is used to simulate and evaluate the operating comfort of the program, and the evaluation results are compared according to the level to exclude unreasonable design solutions. The relationship model between the factors affecting the manipulator box and the design solutions is established by using the hierarchical analysis method. Using hierarchical analysis to establish the relationship model between the factors affecting the manipulator and the design solutions, the optimal design solution is selected after calculating the weights of indicators. The design method realizes the design and evaluation of the cantilever folding control box at the bottom of CNC grinding machine, and provides an effective reference for the subsequent design of related joystick boxes.