Abstract: In order to improve the coupling efficiency and increase the tolerance range of grating coupling packaging structure on silicon substrate, the characteristics of grating coupling structure were analyzed theoretically and verified by simulation based on finite-difference time-domain method. After studying the main influence factors of the coupling efficiency, the basic grating coupling structure was improved without changing the parameters of the grating. A grating coupling structure with lenses was proposed. The results show that, after the lenses are added, coupling efficiency, angle tolerance and bandwidth are optimized through simulation. The coupling efficiency is increased to 73.809% with an incident wavelength in 1550nm when adding the reflectors on the substrate. The analysis results provide a reference for the design of the packaging structure of the grating coupling.