To address large diffraction grating ruling engines' characteristics of micro nano processing at the macroscopic scale and to solve the problem of nanometer scale detection, this paper proposed a method of opto-mechatronics integration optimization. Firstly, computational Fourier optics and the theory of string vibration were used in error analysis. Then, the analysis results were verified by vibration test and optical measurement. Finally, intelligent optimization methods were used to optimize structural parameters. The validity of the opto-mechatronics integration optimization has been verified by simulating a virtual prototype, which has shown that the vibration amplitude of the Scatch System has reduced by 30%.