Rocket on the rope is a new kind of rocket trace test instrument, rocket’s horizontal flight accuracy is affected by the following factors: static tension force, rope’s parameters, side wind’s disturbance and so on. For analyzing the influence of these factors, this paper uses the newton method to construct the rope’s and rocket’s dynamical model, and uses finite element simulation method to calculate the rocket and rope’s 3 dimensional movement. The analysis method raised in this paper applied to the design of a new kind of supersonic rope controlled rocket flight system. The calculation result is close to the rocket’s horizontal deviation characters detected in the early day’s test, it proves the new analysis method’s effectiveness.