It is important for industry products to keep enough adhesive strength between inorganic materials and organic materials. Therefore, various silane coupling agents are employed to improve adhesive strength. Silane coupling agents consist of hydrolyzable group which reacts to an inorganic material and organic functional group which reacts to an organic material. Although the combination of hydrolyzable group and organic functional group should be designed, its variation is huge and difficult to examine by experiments. In this study, we investigated silane coupling agent on adhesive strength with metal layers through first-principle calculation. γ-mercapto propyl trimethoxy silane (MPS) and γ-amino propyltrimethoxy silane (APS) were selected and chromium layer was employ for inorganic materials. The computation indicated cohesion energy of the APS was 59.2% larger than MPS.