We have compared and investigated the detection capabilities of antibody of immunoglobulin G(anti-IgG) immobilized by protein G and N-hydroxysuccinimide(NHS) at the end of the self-assembled monolayer(SAM). Surface plasmon resonance(SPR) sensor has been utilized to measure the interaction between biomolecules. After formation of the protein G and SAM, anti-IgG, bovine serum albumin(BSA) and IgG has been sequently injected. Through the reponse of the SPR, we can conclude that the protein G immobilized anti-IgG better than the SAM. In addition, IgG detection capability of the anti-IgG immobilized by the protein G showed better performance compared with that immobilized by the SAM.