C-reactive protein (CRP) produced by the liver is one of the most characteristic acute-phase proteins. It has been suggested that the level of CRP in human serum may be a significant tool of detecting risks of developing cardiovascular disease and atherosclerosis. Here we propose an advanced plasmonic surface plasmon resonance (SPR) bioassay with Au nanoparticles embedded in the dielectric film that demonstrates a 10X improvement in resolution compared to the conventional SPR biosensor. The co-sputtered film was modified with (3-Aminopropyl)triethoxysilane to sequentially immobilize protein G, monoclonal anti-CRP antibody (C8), and human serum albumins (HSA). After blocked by ethanolamine, the sensor was used to detect CRP. Using this extremely sensitive biochip, the lowest reliable concentration of CRP without any exterior labeling is simplified to human physiological level. The novel assay has the latent capability of not only eliminating the disturbances coming from serum proteins resulting in false signals, but is also able to be applied in rapid and label-free clinical detections of CRP with large improved sensitivity.