Organic matter content is one of the important indices of soil fertility. This paper analyzed the changes of organic matter contents in agricultural soils between 1980s and 2008 in Guangde County, Xuancheng City of south Anhui Province, explored the mechanism of the changes and then put forwards the measures to promote organic matter contents. Generally soil organic matter content in Guangde increased by 1.48 g/kg, i.e., by 6.10%. Soil organic matter content increased in south and middle regions but decreased in north region. Soil organic matter content all increased in paddy soil, dryland soil and garden soil. To promote soil organic matter content, straw-returning-to-field and moderate non/few tillage should be continued, poultry manures and green manures should be applied further.