Optical properties of Au metal nanoparticle have been studied in terms of extinction (scattering+absorption) at the resonance wavelength from UV to IR region. For the spherical geometry having radius 10nm, local electric field intensity distribution were studied at wavelength 615nm. This enhanced field has been couples in the SERS where we increase the sensitivity of the surface to detect a single biomolecule which is adsorbed at the surface of metal nanoparticle. The field profile was studied using COMOL-5.2 which works on the principle of electrodynamics in which the solution of Maxwell’s equation with certain boundary condition is solved. Optimized physical and geometrical parameters was suggested for the application in the field of chemical and biomedical instrument development for the purpose of drug detection and disease diagnosis for cancer detection at the early stage. Copyright © 2018 VBRI Press.