In order to find out and evaluate soil fertility and pollution status of nitrate and ammonia N in ground water in greenhouse vegetable fields of Tai Lake Region, 192 and 54 soil samples, 26 and 10 groundwater samples were collected from the greenhouse and no-covered field respectively in the watershed of Zhihu harbor, and then the contents of mineral N, olsen-P, exchangeble-K, total N, organic matter, the values of pH and EC of soil samples and the contents of nitrate N and ammonia N in the ground water were analyzed. The results revealed that the mineral N content was 279 mg/kg in greenhouse plow layer soil, which was 2.6 times of no-covered. The Olsen-P and exchangeable-K contents were 188 mg/kg and 203 mg/kg respectively in greenhouse plow layer soil, which showed no significant difference between greenhouse and no-covered vegetable fields. N, P and K were easily accumulated in the surface layer of the greenhouse vegetable fields. Organic matter content was 13 g/kg in plow layer soil, which was lower than the classification standard of soil fertility. pH value was 5.6 in greenhouse plow layer soil and 37% of the total cultivated area was below the critical value of the vegetable physiological barrier. 16.4% of the total cultivated area was above the critical value of the vegetable inbreed EC barrier. According to the national sanitary standards in drinking groundwater, the exceeding standard rate of nitrate N and ammonia N reached 35% and 8% respectively.