Based on the research of human-face detection, existing ear-detection methods are investigated in this paper, and a new optimized detecting method is presented to solve difficulties in ear detection such as small region, few common features, complex background and so on. Firstly, images are segmented into different regions with skin-color information and potential candidate regions are selected. Secondly, prior knowledge of side-face is applied to eliminate impossible regions. Thirdly, image edge is detected in different scales and ears are detected according to the rich edge information of human ear. In this method, the skin information of color image and multi-scale edge of grey image are combined with human ear features, which are employed to solve the problem that common features of ear image are difficult to extract in complex background. Experimental results show that this method is effective in complex background.