In order to implement fast target detection for aerial reconnaissance image,an Efficient Subwindow Search (ESS) target detection method based on Ittis saliency map and maximum saliency density is presented.Itti model is used to generate saliency map,then the ESS method based on maximum saliency density is designed.The main idea is to transform the salient target detection into an issue of maximum saliency density,then to localize the maximum saliency density in global optimum using branch-and-bound algorithm.The experimental results show that the proposed method is able to realize fast target detection,with average time cost for target detection of 36.6 ms,and detection rate of 83.2%.