Social development index （SDI in short） is a objective one，and according to Statistical Year Book of each year，eight dimensions of population，education，science and technology，health，social insurance，nature environment，as well as people living were selected to construct the index with 28 indicators. The index reflects the social development of the area and time more totally. The more of the index value and higher of the social development level. Based on computing，SDI of Anhui Province in 2012 is 036，higher than 2011. SDIs of three cities of Tonglin，Huangshan，as well as Chizhou are larger than 0.5 and three cities are listed as top three.