[Objective] This study was to simplify the estimation of phosphorus loss intensity, through identifying key soil properties affecting non-point source phosphorus loss by spectral analysis, in agricultural land of Taihu Basin. [Methods] To identify the key soil physical and chemical properties affecting non-point source phosphorus loss, the spectral characteristics of soil from arable land and orchard land at Meiliang Bay watershed, Taihu Basin were contrasted. [Results] The characteristic bands of non-point source phosphorus loss were 650~670 nm, 1 475 nm and 1 680~1 695 nm in arable land, suggesting that soil organic matter was the main factor controlling non-point source phosphorus loss due to the positive correlation between soil organic matter content and non-point source phosphorus loss intensity. The characteristic bands of non-point source phosphorus loss were 685~690 nm, 710~720 nm, 1 110~1 115 nm, 1 150~1 155 nm and 2 170 nm in orchard land, which suggested that soil organic matter, moisture and Fe²⁺ were the main controlling factors of non-point source phosphorus loss intensity. Non-point source phosphorus loss intensity was negatively correlated with soil organic matter content and Fe²⁺, while it was positively correlated with water content. The effect of the source phosphorus loss on the arable land was more significant. The correlation coefficient between the surface source phosphorus loss intensity and the spectral index reached 0.74 at 1 685 nm in arable land. The highest correlation coefficient was only 0.48 at 715 nm in orchard land. [Conclusion] The key soil property in arable land was soil organic matter, and the key soil properties in orchard land was soil organic matter, moisture and Fe²⁺.