The flexible finger is composed of dual-muscle-driven unidirectional bending joint and a single-muscle-driven unidirectional bending joint in series.It has two degrees of freedom and has the characteristics of large deformation and nonlinearity during bending.According to the deformation law of the finger,the kinematics equation of the finger were established by using the D-H method and the corresponding Jacobin matrix of forces was deduced.The forces of the fingertip were analyzed when they were clamping objects,and the mathematical model between the fingertip clamping forces and the air pressure increment of each joint was established.The model shows that the output forces of the fingertip is approximately proportional to the air pressure increment of each joint.Through the combination method of MATLAB simulation and experiment,the output force of the fingertip was studied.The simulation results of the model and the experimental results have little error and basically consistent,which verifies the accuracy of the model.