A 7-year field experiment was conducted on the dry land of red soil derived from Quaternary red clay in the middle subtropical zone under the same carbon input from organic materials in corn monocropping system, and the effects of different organic material application on soil phosphorus fractions using different phosphorus fraction methods, the correlation between different phosphorus fractions with soil total phosphorus and available phosphorus, and the effects of different phosphorus fractions on soil phosphorus activation coefficient (PAC), the apparent and economic utilization rates of phosphate fertilizer were studied. The results showed that the application of organic materials increased soil PAC and the utilization rates of phosphorous fertilizer, and the best effect was obtained by applying 9∶1 (NPKS/M) with straw pig manure, which was significantly higher than those of conventional fertilization treatment (NPK). The application of organic materials significantly increased the content of soil organic phosphorus, which was significantly positively correlated with the content of soil available phosphorus, thus, had significant effects on soil PAC and the apparent and economic utilization rates of phosphate fertilizer. In addition, the application of organic materials also affected the availability of soil phosphorus by affecting the contents of soil organic carbon, total nitrogn, auailable nitroger, exchangeable K⁺ and Al³⁺.