This paper firstly describes the preliminary results achieved by using palladium nanoparticle (Pd NP) as a novel label for the detection of DNA hybridization in DNA microarray. And two signal amplification procedures based on "the silver staining" or "the cobalt staining" are presented during above analysis. The results show that the label Pd NP-ssDNA (target) (single strand DNA(target)) performs high single base pair mismatch-discrimination capability. The succeeding silver staining or cobalt staining procedure greatly amplifies such a signal through the catalysis of Pd. For "the silver staining:' the background staining is very low and the silver deposition only occurs around Pd NPs. So such a procedure provides a alternative for "Gold Label Silver Stain" presented by Mirkin C. A. For "the cobalt staining," not only a colorimetric array but also a magnetic sensor (such as Magnetic Tunnel Junction sensor, MTJ) can be used to detect the obtained cobalt dot due to its strong magnetic property, which provides a new strategy for DNA microarray detection. So as the proof-of-concept investigations, this work proved the feasibility of the application of Pd NPs as the label in DNA microarray assay.