Here, we present a novel insulator-based dielectrophoresis (DEP) device integrated with nanorod arrays for highly effective and rapid protein enrichment and detection. Dense arrays of Ag nanorods coated with oxide are fabricated on glass wafers prepatterned with microelectrodes; therefore creates a super high electric field gradient and concomitant adequate dielectrophoresis force for trapping of proteins. The fabrication process exploits oblique angle deposition (OAD), a physical vapor deposition method, for easy integration of nanostructures in DEP devices. This technique employs the shadowing effect and surface diffusion of adatoms, which eliminates the requirement of advanced lithography equipment. Leveraging on this platform, enrichment of bovine serum albumin (BSA) protein is demonstrated by 1800-fold with 180-fold/s when only applying 5 V electric potential at 1MHz. Further, the immunoassay of a tumor biomarker, carcinoembryonic antigen (CEA), with femtomolar sensitivity (~7.5 fM) is realized using this platform, referring to a 4,300-fold enhancement in the detection limit compared with identical assays performed on blank glass plates. The enrichment of proteins also accelerates the binding kinetics and enables signal saturation within one minute.