There is currently intense interest in the use of nanoparticles for a wide range of biomedical and technological applications.In this paper,the hierarchical Co doped ZnO nanoflowers were synthesized by a facile wet chemical method and explored as biosensing material.The as-modified novel hydrogen peroxide sensor exhibited a wide linear range(0.25–20 mM),highly reproducible response(R.S.D.of 2.7%) and long-term stability.The doping Co2+ions carried out the oxidations rapidly and efficiently for the catalysis of hydrogen peroxide(H2O2).A high activity toward H2O2in the presence of ascorbic acid (AA) and NaNO2, which are only common for natural enzymes, has also been demonstrated. The good analytical performance, low cost and straightforward pre-paration method makes this doped semiconductor promising for a wide range of potential applications in medicine,biotechnology and environmental chemistry.