Two kinds of vegetables (lettuce and Chinese cabbage) were used in a hydroponic experiment on effects of nitrogen form and foliar spraying of nitrate-lowering agents on nitrate accumulation in the vegetables growing in nutrient solution. Results showed that the effects of nitrogen form were significant on growth and nitrate accumulation of lettuce and almost not on Chinese cabbage. When receiving the same form of nitrogen, Chinese cabbage was found significantly higher than lettuce in nitrate concentration in leaf, suggesting that the accumulation of nitrate is determined by inherited characteristics of different vegetables. The effects of foliar spraying of two kinds of nitrate-lowering agents were not significant on lowering nitrate content in vegetables.