Abstract: The paper aims to study the environmental indicators of soil phosphorus in farmland. By summarizing the researches on the environmental indicators of soil phosphorus from 1984 to 2014, it was found that the research on the environmental indicators of soil phosphorus in farmland had a rapid progress even though it started late. Through the researches on the loss pathways and erosion forms of the soil phosphorus in the farmland, it showed that the available phosphorus content in different forms such as water soluble phosphorus and particulate phosphorus in soil had a significant correlation with surface runoff phosphorus content. The phosphorus content of the water body had a high correlation with the content of soil Olsen-P. It was accurate and reliable to regard the soil Olsen-P as the environmental index of soil phosphorus in the farmland. Domestic and foreign research results showed that the Olsen-P environment threshold of the target water body as lake and river was 25 mg/kg and 75 mg/kg, respectively. Exceeding the critical value, the phosphorus content in soil runoff and drainage and fluid leakage would significantly increase, which led to the risk of increasing soil phosphorus loss from farmland into the water. The pollution and eutrophication of water bodies would emerge. However, the research on the environmental indicators of soil phosphorus in the farmland still has many deficiencies. In the future, we need to study the reduction coefficient of the soil phosphorus in the process of loss, as well as the interaction mechanism of the soil phosphorus in farmland through surface runoff and soil erosion.