Abstract: Results obtained from investigation at intensive agricultural region in Huanghe-Huaihe-Haihe Plain demonstrate that nitrate pollution of ground water is serious in high-yield agricultural region and in high-yield farmland.Nitric nitrogen content in ground water is higher in vegetable-land than in grain land.Nitrate content in ground water accumulates obviously with the increase of N-fertilizer applied,so the potential pollution should not be ignored.Nitric nitrogen content in ground water has positive relation with the amount of N-fertilizer applied.