In order to segment the extern contours of hip joint correctly and effectively, a kind of extraction method for extern contour of proximal femur is presented based on the best segmentation curve. The proposed method can find a closed segmentation curve which segments target femur part against remaining femur part by the virtue of frame similarity for bottom up CT image sequences, so as to locate the position of the target femur accurately, and search for the edge point by the virtue of the segmentation carv...