1. An image segmentation method, comprising: classifying the pixels in the image according to the color values of pixels, wherein pixels with the same color value are classified into a color type; establishing a saliency model according to the color value of each color type, wherein the saliency model is: S i ⁢ ⁢ 2 = ∑ j = 1 , j ≠ i N ⁢ w ⁡ ( P j ) ⁢ D C ⁡ ( P i , P j ) , wherein w(P j ) is the number of pixels in a color type R j , D C (P i , P j ) represents a metric value of difference in color between the color type P i and the color type P j ; obtaining foreground sample points and background sample points of the image according to the saliency model; establishing a foreground and background classification model according to the saliency model, the foreground sample points and the background sample points; and segmenting the image according to a predefined graph cut algorithm by using the foreground and background classification model and edge information related to pixels in the image.