By calculating the Theil index to measure the regional disparity in Guangdong from three dimensions：region，city and county，and comparing it with Jiangsu’s and Zhejiang’s，we get the characteristics of regional disparity in Guangdong，and further analyze the causes of regional disparity from several points. Finally，based on experiences outlined from Zhejiang and Jiangsu，we give policy suggestions on reducing the regional disparity in Guangdong.