In order to improve the safe and sustainable utilization of phosphorus in high-fertility soil, and explore the C∶P ratio of high-fertility soil. Soil of three typical crop types (grain crop-maize, local characteristic high value economic crop-tobacco and vegetables with high value and high nutrient input) from 27 sample sites in Erhai Lake Basin were selected to analyze the characteristics of soil carbon and phosphorus content and C∶P ratio. The results showed that: (1) The soil organic carbon (SOC) content was 31.91 g/kg, and there were no significant difference in SOC content among the different crop types. (2) The contents of available inorganic phosphorus (NaHCO₃ extracted inorganic phosphorus, NaHCO₃-Pi) and available organic phosphorus (NaHCO₃ extracted organic phosphorus, NaHCO₃-Po) were 156.7 mg/kg and 63.43 mg/kg, respectively. There were no significant difference in the contents of available inorganic and organic phosphorus (NaHCO₃-Pi/NaHCO₃-Po) among the different crop types, and the results were as follows: vegetable field ＞ tobacco field ＞ maiza field. (3) The C∶NaHCO₃-Pi ratio and C∶NaHCO₃-Po ratio of farmland soil in Erhai Lake Basin were 321.42 and 1138.25, respectively. The C∶NaHCO₃-Pi ratio of farmland soil in Erhai Lake Basin was significantly lower than the China and the southwest China. The C∶NaHCO₃-Pi ratio of vegetable field was significantly lower than that of maize field. Our results showed that the soil carbon and phosphorus content in Erhai Lake Basin was high, especially the high phosphorus content, leading to a significant decrease in soil C∶P ratio. The C∶P ratio of high input vegetable land was significantly lower than that of maize field, which not only impacted the transformation of phosphorus by soil microorganisms, but also brought about phosphorus pollution. Therefore, the safe and sustainable utilization of phosphorus in high fertility soil can be achieved by regulating the C∶P ratio. Adding materials with high C∶P ratio, such as crop straw, can increase the soil C∶P ratio, increase the immobilization of soil phosphorus by microbes, and store soil phosphorus in microbial phosphorus pool, which can reduce the loss of soil phosphorus to water.