The straightness error of the guide rail in the horizontal plane not only affects the workpiece machining accuracy,but also may lead to the change of cutting force.The current straightness error of guide rail is mainly solved by manual calculation or relying on measuring instruments,with low measurement accuracy and complex calculation.To solve the problem,taking numerical control lathe guide rail as the research object,the graphic programming software LabVIEW was used to design the linearity error analysis system of the lathe guide rail.The system has functions such as reading measurement data,analyzing straightness errors,and saving calculation results.It is proved that the system runs well,with fast data analysis speed,intuitive calculation result and high precision,and the automation and visualization of guide straightness error analysis is realized.