Rapid development of microanalytical devices has provided convenience and capability for disease diagnosis, drug screening, or forensic applications. Optical detection of DNA hybridization usually needs to detect a fluorescent signal by large and expensive optical equipment. Electrochemical detection offers great promise for rapid, simple and low-cost detection of specific nucleic acid sequences. A label such as enzyme labels or electroactive labels have been introduced to improve the sensitivity of the electrical assays. However, development of methods that do not require additional instrumentation and reagents is still a challenge for point-of-care or field use. Efforts on label-free electrical DNA hybridization have encountered problems of random orientation of thiol-modified oligonucleotide probes thus unreliable signal output. Here we report a nanoparticle-based electrical detection of DNA hybridization. A well-controlled mixed self-assembled monolayer method is adopted for the immobilization of thiolated-ssDNA. Electrochemical Impedance Spectroscopy is applied for the detection of DNA hybridization on gold electrodes. By using AFM, we proved that Au nanoparticles are on the biosensor surface for specific DNA hybridization after stringency wash. The results indicate that nanoparticle-based electrical DNA hybridization detection provides a rapid, robust, low-cost and sensitive detection scheme which has great potential for hand-held microarray technologies.