Designs for conventional ducted wind turbines usually include a large inlet for more absorption of the airflow. However, the most efficient solution should be increasing the speed of wind. In this paper, a bucket-shape ducted wind turbine is proposed and studies show that it sticking effect can be produced according to the Bernoulli's principle, and this significantly increases the wind speed inside the duct and substantially enhances the efficiency of the wind turbine. Moreover, the geometry of the duct is optimized by the combination of an improved complex algorithm, an object-oriented optimizing program interface, and simulations by CFD software. According to the analyses, the optimal shape for the interior of the duct appears to be ail unconventional nozzle, which extends the range of wind speed by 60%. Based on this bucket duct equipped with the optimal nozzle, we have practically designed and constructed a wind power generator. The results of the field tests show that the proposed ducted turbine does improve the flow around the generator and thus increase its power extraction efficiency by about 80%. (C) 2007 Elsevier Ltd. All rights reserved.