The characteristics of runoff and nitrogen loss in sloping cropland of purple soil during corn growth stages were carried out to provide a theoretical basis for the prediction and effective prevent of nitrogen loss in sloping cropland. Simulated rainfall combined with runoff plot experiments (1 m×2 m) was employed during each corn growth stage, including seedling stage, elongation stage, tasseling stage and maturity stage. The rainfall intensities were set as 1.0 mm/min, 1.5 mm/min and 2.0 mm/min. The results indicated that the runoff in soil surface and nitrogen loss increased with the increasing rainfall intensity during corn growth stages. Total runoff in the seedling stage was significantly higher than that in other growth stages. The average concentration of nitrogen loss in the elongation stage was up to 16.36 mg/L. The average amounts of nitrogen loss obtained the maximum value of 10.24 mg/m2 at the seedling stage, and the minimum value of 2.97 mg/m2 at the tasseling stage. For the nitrogen forms, ammonium nitrogen and nitratenitrogen accounted the greatest part of nitrogen loss at seedling stage and maturity stage of corn, respectively, and the loss of ammonium nitrogen and nitratenitrogen was the least at the tasseling stage of corn. During the whole growth stages of corn, nitratenitrogen was the main nitrogen form in the runoff of surface soil and accounted 77.98%~97.85% of the total nitrogen loss. The concentration of nitrogen loss was the highest in the elongation stage, and the nitrogen loss amount was the greatest in the elongation stage of corn. Nitrogen loss in the seeding and elongation stage of corn could easily lead to the eutrophication in waters. Thus, it was necessary to cut the application of base fertilizer and top dressing of nitrogen, and increase vegetation cover to reduce nitrogen loss in runoff.