In high speed, the web press’s fold mechanism appears nonlinear dynamic response characteristics, which seriously affect the fold system’s stability and precision. The clearance and roller’s deformation are the main factors to cause the nonlinear dynamic response. To study the influence of clearance and roller’s deformation, the hypothesis of rigid role and spring combination is put forward. Based on the hypothesis, the dynamics model of fold system with clearance is established by kinematics and dynamics analysis. Through the dynamics model of fold system, the situation of pair clearance and roller’s deformation can be obtained, and the influence to the dynamic performance of fold system can be easily got.