Optical　frequency　comb　plays　an　important　role　in　the　field　of　ultrafine　optical　signal　detection　and　microwave　photon　signal　processing,Lithium　niobate(LN)has　high　nonlinear　coefficient　and　excellent　electro-optical　characteristics,the　electro-optical　modulator　based　on　lithium　niobate　thin　film　has　the　advantages　of　low　power　consumption　and　high　integration.In　this　paper,a　cascaded　intensity　and　phase　modulator　based　on　lithium　niobate　thin　film　is　designed.　The　scheme　of　cascaded　intensity　modulation　and　phase　modulator　generating　optical　frequency　comb　is　verified　by　simulation,and　minimum　bending　radius　of　the　thin　film　modulator　is　optimized　by　parametric　scanning　by　finite　element　method　to　determine　the　optical　mode　limitation　in　the　ridged　waveguide.　In　order　to　further　reduce　the　half-wave　voltage　of　coplanar　waveguide　electrodes,a　multi-variable　constraint　algorithm　is　used　to　co-simulate　the　relationship　between　overlapping　integral　and　half-wave　voltage　by　optimizing　the　thickness　of　buffer　layer　between　electrodes.　©　2023　SPIE.