A terminal cutting mechanism with variable step length was which applied in cutting and pressing connection for terminals. It could realize feeding, clamping, and the terminal cutting number could be adjusted between 2~6. A three dimensional solid model of the variable step length cutting mechanism was established by using UG/Modeling function, and the kinematic characteristics of the 3D solid model of the designed mechanism were analyzed by using UG/Motion simulation. The mechanism has no interference in the dynamic process by modeling and the analysis. The stress and strain of the moving parts of the mechanism were analyzed by using the advanced UG simulation graphics, reliability test was done for the points on the mechanism with highest stress and most easily deformation. The finite element analysis shows the stress and strain of the moving mechanism are linear and much lower than the stress allowable value of the mechanism, so the design of the moving parts meets the requirement.This mechanism has issued the invention patent, and the productive pilot is finished in partner enterprise; the feasibility of this mechanism is proven by the testing.