The nonlinear dynamic behavior of the slideway-joint system of machine tools is studied. Taking into account the hysteretic characteristics of this system in contact vibration, a mathematical model for dynamic analysis is established. By means of asymptotic method, the coefficients of damping and stiffness equivalent to the hysteresis are obtained. Range-Kutta method is used to solve the system equation. The nonlinear dynamic responses of the guideway-joint system for different damping coefficients are discussed. The result shows that the chaotic vibration will occur when the damping oefficient varies in some range.