Massive ZnO nanowires with the mean diameter of 20 nm have been rapid synthesized by evaporation of metal zinc at 900 °C in the quartz tube. Metal catalyst, graphite additive, and vacuum are not necessary, and, more importantly, it is very convenient and effective for large-scale industrialization. The hydrogen storage characteristics of the synthesized ZnO nanowires are investigated at room temperature. The highest storage capacity of 0.83 wt% is achieved under the pressure of about 3.03 Mpa, and about 71% of the stored hydrogen can be released under ambient pressure at room temperature. © 2004 American Institute of Physics.