The effects of different cropping systems on content of nitric nitrogen in soils and vegetable were studied. The results indicated that, there is more nitric nitrogen in vegetable soils in green-houses, followed by opened vegetable soils, and then traditional vegetable soils; there is more nitric nitrogen in greenery vegetable in green-houses, followed by leguminous vegetable, and then melon vegetable, the lowest nitrates were found in nightshade vegetable. Nitric nitrogen in greenery vegetable exceed level I standard, pollution index is up to 3.50; Nitric nitrogen leguminous, melon and nightshade vegetable is below level I, which indicates these vegetable are light polluted.