This study explored the effects of four furrow slopes (0°, 9°, 18° and 27°) on the concentrations and losses of PO₄^3--P, NO₃^--N and NH₄⁺-N through simulated rainfall experiments, and evaluated eutrophication risk of the runoff by the ratios of Inorganic-N/PO₄^3--P, NH₄⁺-N/PO₄^3--P, and NH₄⁺-N/PO₄^3--P. The results were as follow:(1) PO₄^3--P, NO₃^--N, and NH₄⁺-N concentrations changed in the shape of wavy serrated shape with rainfall time under four furrow slopes. As for losses, their maximum value (16.60, 1 020.73, 48.35 mg) appeared in 0°, 0°, and 9° when they increased firstly and then changed in zigzag shape with rainfall time. (2) Under different furrow slopes, PO₄^3--P and NH₄⁺-N losses in runoff water were in order of 0° > 9° > 27° > 18°, whose concentration maximum value (0.50, 1.08 mg/L) and minimum value (0.37, 0.76 mg/L) appeared in 9° and 18°. NH₄⁺-N concentration and losses maximum value (30.68 mg/L and 64.16 mg/m²) and minimum value (21.78 mg/L and 42.22 mg/m²) appeared in 0° and 18° in runoff water. (3) The ratios of Inorganic-N/PO₄^3--P and NH₄⁺-N/PO₄^3--P showed that four furrow slopes output runoff all had eutrophication risk, and the 0° output runoff of that was the highest and the 27° was the lowest. These findings would provide scientific guidance for evaluation, prediction, and control of soil and water loss and nutrient loss in contour ridge system.