The main characters of the helical fin tube rotary rolling process were introduced and geometric model was built to analyze the kinematic relationship between the roller and tube, such as angular velocity and relative velocity in sliding area. Velocity distribution was investigated in the form of component velocity in the deformation zone. The results show that both circumferential velocity and axial velocity increase along the rolling direction and the rising rate of circumferential velocity is much higher than that of axial velocity. Thereby the circumferential twist and the axial elongation occur on helical fin tube rolling workpiece in roll process. Twisting rate was introduced here to describe the variation of angular velocity along the rolled tube. Using the given expression, the influence to twisting rate by the main factors, such as roll speed, relative reduction, center distance and roller radius can be obtained.