Based on the measurement and evaluation principles of flatness,straightness,parallelism,the parallelism of precision guide rail with effective stroke of 2 000 mm was measured,and the angle deviation,straightness,and guide rail parallelism of both a single slider and slider pairs of the guide rail workbench were theoretically analyzed and verified by experiments .The results show that under the same circumstance and assembly process conditions,the angle deflection direction and trend of the slider in the horizontal plane are almost identical,and the maximum angle deviation of the slider is similar.The four sliders in the horizontal plane belonging to a guide rail workbench are concave in the middle of the straightness curve.In the vertical plane,the straightness is affected by the assembly locking force and angle deviation.The rotation direction of the angle deviation is the same,but the trend is slightly different; the direction of the straightness of both a single slider and the slider pairs is consistent.Due to the average effect of the force on the slider pairs,the straightness of the slider pairs in the vertical and horizontal planes is better than that of a single slider.The method evaluating the parallelism between guide rails based on the absolute value of the straightness slope algebraic operation of the reference guide rail and the auxiliary guide rail can provide a guideline for the measurement of precision guide rail parallelism.