Abstract: In carpet tufting process,the mechanical properties of tuft needles restrict the raising of the spindle′s speed and also influence the vibrational property of the entire mechanical system of a tufting machine.However,the kinetic characteristic of the needles greatly depends on the mechanical design of the driving mechanism.This paper introduces the basic principle of carpet tufting motion,designs a needle′s driving mechanism which consists of a crank and slide. Mathematical analysis is made of the crank driving mechanism.Kinematical analysis and comparison of the driving mechanism under the condition of different crank parameters are conducted using ADMAS simulation software with emphasis on the needle movement and the force exerted upon it when punching into the substrate. The optimal design parameters for the crank are determined.The achievements of this research have been applied to the design of carpet tufting machine(DHT200.)