Polypropylene (PP) slice was treated with plasma in a mixture of nitrogen and hydrogen (1:2 V/V). Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) demonstrated the successful grafting of amino groups. The as-treated slices were successively applied to the in-situ synthesis of oligonucleotides and an average coupling yield of more than 98% was achieved. The hybridization signals were recorded with fluorescent analysis system. The complementary and mismatched sequences were distinguished clearly, and the ratio of fluorescence intensity values (arbitrary units) for perfect match:single base mismatch:two bases mismatch:three bases mismatch is 108.6: 62.9: 22.4: 5.5. The results implied the plasmamodified PP surface was extremely stable, performed well in DNA hybridization assays, and could service as a good substrate for high-density oligonucleotide array synthesis, especially in a multistep molecular stamping method to fabricate DNA microarrays in-situ on a large scale.