Abstract: In the machining process of high-speed and high-precise machine tools, the friction heat can cause thermal deformation of the slide guide. Former study on the thermal characteristics of the slide guide get the analytic solutions of the slide guide's thermal deformation by traditional calculation method. It neglects the effect of heat source movement on the slide guide thermal deformation, and the results are thus not accurate. Taking such effect into account, the finite element model of the slide guide was built. The temperature field of the slide guide was obtained by numerical simulation. The thermal deformation of the slide guide was further achieved. The deformation decreases 2.52 μm as compared with that of stationary analysis. The slide guide reaches a thermal balance in about 1.25 hours. The maximal straightness error at the horizontal plane is 5.03 μm, while the maximal gradient error on the surface of slide guide is 0.0002189°. The result provides some basis for understanding the effects of the slide guide thermal deformation on the machining accuracy and furthermore for the error compensation of machine tool.