Graphene-silicon nitride optoelectronic devices have good performance in optoelectronic integration, but the visibility of transferred graphene on silicon nitride is usually not good, which makes it difficult to judge the quality of transferred graphene. Therefore, it is of great significance to study the visibility of graphene on silicon nitride. This paper first derives the theoretical calculation formulas for the optical reflectance and the optical contrast of graphene on the multilayer structure based on the Fresnel formula, and then uses MATLAB to simulate and analyze the influence of silicon oxide thickness on the optical contrast of graphene on the silicon nitride/silicon dioxide/silicon multilayer structure. The simulation results show that the optical contrast of graphene can increase significantly under the specific thickness of silica layer, which makes graphene clearly visible under microscope and can better judge the transfer effect of graphene. When the silica thickness is 2 547 nm, the contrast between graphene and surrounding medium can exceed 0.3. Lastly, two samples with SiO2 thickness of 2 330 nm and 2 690 nm were fabricated and tested. The analysis reveals that the main reason is the deviation of material deposition thickness and light source wavelength, which provides guidelines and indications for the further improvement of device fabrication and test methods.