Abstract: Applying the theory of relativity,the traveler movement was resolved into the traction motion and the relative motion,and the equation of the space motion of the traveler and the space position coordinate of the center of gravity of the traveler were obtained.Then,based on the principle of dynamics and the theory on the ballon for ring spinning,the force acting upon the traveler during spinning was analyzed,and the dynamical equation of the traveler in motion was derived,thus providing a theoretic basis for the correct design of the traveler.Finally,some examples were presented for calculating the space position of the traveler by making use of the MatLab.