A grating diffractive spectral imaging model with ruling line bend and ruling line position errors was established based on the Fresnel-Kirchhoff diffraction theory, and the effect of these errors mentioned above on grating spectral properties was analyzed. For the instability of ruling carriage system, an optical measuring system was designed, and a mechanical improvement for the ruling carriage system was proposed.It was implemented by adopting a bilateral flexible hinge structure to replace the fixed linking method of original saddle slider pattern and ruling carriage system. Finally,The experiments on the stability test of ruling carriage system and the grating ruling test were performed. The experiment on the stability test of ruling carriage system shows that running stability of the improved score tool holder system is improved significantly as compared to that before improvement,and the displacement curve repeatability error (PV value) has reduced from 127 nm to 13 nm, decreased about 89%. Moreover, the grating ruling experiment shows that the grating spectrum performance after improving ruling carriage system has improved greatly,and the stray light has been effectively suppressed. These results obtained are in agreement with that of simulation, and provides theory and technological bases for improving grating ruling quality.