To solve the measurement problem of stroke error for heavy⁃duty screw pairs with diameters of 100 ~ 300 mm in key industries, building upon the experience of small and medium⁃sized screw measurement instruments, this study has optimized the overall configuration, critical components, and measurement⁃control systems while exploring manufacturing and assembly processes. A specialized measurement machine for heavy⁃duty screw pairs was successfully developed, enabling dynamic measurement of both lead error in heavy⁃duty screws and travel error in screw pair assemblies. Experimental results demonstrate that within a 4 m travel range, the instrument's optical axis exhibits maximum indication errors of 0.5 μm and 1.3 μm when positioned at 50 mm and 150 mm from the screw centerline, respectively. For the tested screw pair samples, the maximum deviations between the extreme values of all measured parameters do not exceed one⁃third of the tolerance specified for P1⁃grade screw pairs. These findings confirm that the measurement accuracy of this heavy⁃duty screw pair stroke measuring machine meets P1⁃grade requirements. The successful development of this instrument plays an important role in promoting the development of heavy⁃duty screw pairs and screw detection fields.