According to the characteristics of radial tire technological process, a new type of tire building drum was proposed. The kinematics analysis was carried out based on the systematical study on the structure and working principle of this mechanism. And on this basis, taking passenger car tire for example, the three-dimensional solid model of the tire building drum was established, and the kinetic simulation was performed by Solidworks software. The result of simulation shows that the tire building drum proposed, with inside-outside alternating supporting shells moving smoothly, is of simple construction and can realize a great radial expansion ratio, and improve the quality and efficiency of tire building and unloading. This study can also provide reference for the innovative design of new tire building drum.