For the same multi-link kinematic chain, selecting different links as driving links will create different mechanisms to implement different functions. Therefore, identifying driving links has important significance to create new mechanisms. The paper presents a concept of the mobility factors of the kinematic chains. By analyzing single loop mobility factor, an identification method of the driving links in multi-link kinematic chains is presented. The mathematical model is established. A program is developed which can achieve the automatic identification the driving links in multi-link kinematic chains. Case study verifies the effectiveness of this method and automatic identifies the driving links of a part of 3-DOF 12-link kinematic chain. The identification method can also apply to spatial kinematic chain.