Abstract: In order to solve the problem that 2-D minimum error threshold segmentation (METS) method had poor segment robust performance on an image which presents skew distribution and heavy-tailed distribution, an improved 2-D METS method was proposed based on mean absolute deviation from the median. Considering that the median was a more robust estimator of gray level than the mean in 1-D histogram of skew distribution and heavy-tailed distribution, variance in 2-D METS was replaced by mean absolute deviation from the median. In order to improve the computational speed, a 2-D algorithm was decomposed into two 1-D algorithms. Experimental results show that, compared with 2-D Otsu method, 2-D METS method and other classical algorithms, the improved 2-D METS method based on mean absolute deviation has more accurate segmentation results and more robust performance for 1-D histogram with skew distribution and heavy-tailed distribution.