In this paper, three different kinds of ZnO nanostructures were successfully synthesized on Au/Glass (Au/G) substrate by electrochemical deposition method. The morphology and crystalline structures of the obtained samples were characterized using SEM, XRD and HRTEM. Electrochemical responses of the as prepared ZnO based sensors to hydrazine in 0.1 M phosphate buffer solution (PBS, pH 7.4) were analyzed by cyclic voltammetry and single-potential amperometry. The results confirmed that the electrochemical performances of ZnO sensors are strongly dependent on the specific surface area. Especially, the branched hierarchical ZnO nanorod arrays shows the highest sensitivity of 5.35 mu A mu M-1 cm(-2), a short response time of 3 s, a low detection limit of 0.08 mu M with a linear hydrazine concentration response range from 0.8 mu M to 101 mu M, and it also exhibits excellent anti-interference, stability and reproducibility abilities, which provide great potential method of ZnO branched hierarchical structures in the development of high-performance electrochemical sensor. (C) 2015 Elsevier B.V. All rights reserved.