Ball screw is the core of precision servo drive system components, with the screw to run, the temperature will lead to increased singleaxis screw servo system straightness error. In order to clarify the error and its generating rule, a thermal error model of the ball screw is established, and the heat source, temperature field and thermal error model of the ball screw pair are studied respectively. According to the structural characteristics of the ball screw, the distribution rules of the heat source and the temperature field are determined, and the characteristics of thermal error are analyzed. Design experiment, test the straightness error before and after the temperature change, pass 5 minutes interval to run, clear the temperature and straightness error of the process of change and the law. The experimental results show that, with the temperature rise, screw straightness error with the screw itself bending state will appear more obvious bending, remove the screw itself exists straightness error and calibration process slope error, straightness The error is increased by 11.4μm. In this paper, the error of screw straightness with temperature is obtained, which can be applied to the verification and compensation of the overall geometric error of other space driving systems, which has a strong engineering application prospect.