This study investigates the dynamics of 3-dimensional pinching movements by dual two degree-of-freedom fingers with redundant muscles.The pinching movements are realized by the finger-thumb opposition.Both the thumb and index finger adopted the model with one monoarticular muscle and two biarticular muscles.During the pinching movements,the object may rotate along two axes so that it may achieve time-varying in 3-dimensional pinching.The dynamics and stability of the pinching movements are analyzed taking into account the co-contraction between the flexor and extensor muscles as well as the nonholonomic constraints.The numerical simulation is performed with a simple control signal to verify the effect of gravity.