A method of fabricating a biosensor chip includes: forming at least one metallic layer on a transparent substrate to form a composite member; disposing the composite member in a vacuumed chamber, and introducing a gas into the vacuumed chamber; applying microwave energy to the gas to produce a microwave plasma of the gas within the vacuumed chamber, and causing the microwave plasma to interact with the metallic layer so that the metallic layer is melted and formed into a plurality of metallic nanoparticles that are spaced apart from each other and that expose partially the surface of the transparent substrate; and disposing a receptor at the surface of the transparent substrate that is exposed among the metallic nanoparticles. A biosensor chip is also disclosed.