Abstract: In order to optimize water and nitrogen coupling for cucumbers in the oasis greenhouse, we used the cucumber variety Excellence 99F1 with a random complete block design to investigate the effects of different irrigation and nitrogen coupling on cucumber nitrogen metabolism, yield and quality.The results showed that, the treatment of 65%~80% field water holding capacity and nitrogen application of 234 kg · ha^-1 (W2N2) had higher nitrate reductase, glutamine synthetase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase activities than those of other treatments.The nitrate reductase, glutamine synthetase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase activities were in the order of mid > early> late-fruiting stage, respectively.The interaction of irrigation and nitrogen on nitrate reductase, glutamine synthetase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase activities in the mid-fruiting stage was significant.The cucumber plants under W2N2 treatment showed the largest values of development spread, yield per plant, and economic yield, with 71.4 cm, 4.17 kg, and 174 t · hm^-2, respectively.Irrigation and nitrogen interactively affected plant height, leaf number, development spread, yield per plant and economic yield.The W2N2 treatment was with the highest soluble sugar content, soluble protein and fruit Vc contents in the fruit.Therefore, the interaction of irrigation and nitrogen would significantly influence the soluble sugar content of cucumber fruits, and nitrogen fertilizer would significantly impact soluble protein and Vc concentrations in the fruit.