：The disadvantages of the current thermal error compensation methods for CNC machine tools’ feed drive system are analyzed,such as the requirement of many temperature sensors and poor robustness of models. A strongly robust modeling method without temperature sensors for half-closed-loop feed drive systems is proposed to realize the compensation for thermal errors induced by moving in a constant temperature environment. The thermal error modeling and parameter optimization procedure using ISIGHT are presented. Based on the heat production,heat conduction and heat convection theory,the ball-screw’s temperature field can be obtained to predict and compensate the ball-screw’s thermal error. Experiments are conducted on a vertical machining center VMC850,and the simulation results of the model are presented. Comparative experiments through laser interferometer test and machining are conducted on another vertical machining center VMC850. The results show that the proposed modeling method owns high accuracy stability and strong robustness.