Diazotrophic community structure in an upland red soil under 26-year fertilization practices was studied using Illumina MiSeq sequencing in our project. The aim of our project was to examied the potential shift of diazotrophic community structure under 26-year organic and inorganic fertilization in the upland red soil of southern China. The soil was derived from quaternary red clay and classified as a Typic Plinthudult (Ultisols) based on the US Department of Agriculture soil taxonomy. Soil had 41.2% clay, 33.2% silt and 25.6% sand. Seven different fertilizer treatments were chosen: no fertilizers (Control), inorganic NPK fertilizer (N), inorganic NPK fertilizer plus liming (CaCO3) (NL), and inorganic NPK fertilizers plus peanut straw (NPS), rice straw (NRS), fresh radish (NFR), and pig manure (NPM).