A 2-year field experiment was conducted to determine the effects of nitrogen fertilizer rate and irrigation amounts on grain yield, nitrate accumulation and nitrogen balance on sandy farmland in the marginal oasis in the middle of Heihe River basin. Experimental treatments included three irrigation levels (conventional irrigation: 12000m3 hm-2, 10% (2006) or 12.5% (2007) water-saving irrigation, 20% (2006) or 25% (2007) water-saving irrigation) and five N rates (N1, 0 kg hm-2, N2, 150 kg hm-2, N3, 225 kg hm-2, N4, 300kg hm-2, N5, 375 kg hm-2). Nitrogen fertilizer application increased maize yield by 48.22%-108.6% compared with no nitrogen fertilizer treatment. However, maize yield, N uptake and use efficiency in total aboveground biomass and in grain did not increase significantly at N rates more than 225 kg hm-2. There were three peak values of NO-3-N content in the 0-20 cm, 140-160 cm and 260-300 soil layer as affected by soil texture and the peak values increased with increased N rates. Irrigation amount obviously influence NO-3-N accumulation in soil profile. The NO-3-N accumulation in the 200-300 cm layer was generally higher under conventional irrigation level than under the two water-saving irrigation treatments. However, NO-3-N accumulation in the 0-100 layer was higher under 20%-25% water-saving irrigation treatments than the other two irrigation treatments. The result indicated that more amount of NO-3-N was leached into deeper soil layers under conventional irrigation amount. The NO-3-N concentration in the 0-200 cm depth under no N fertilizer treatment was significant lower in 2007 than in 2006. The amount of NO-3-N accumulation in the 0-200 cm depth ranged from 27.66 kg hm-2 to116.68 kg hm-2 and the amount of apparent losses ranged from 77.35 kg hm-2 to 260.96 kg hm-2, which had significant and positive correlations with N fertilizer rates (R2: 0.788 and 0.987). With the increase of application rates, total N uptake and N harvest index increased, but N use efficiency decreased. It is concluded that 10%-25% water-saving irrigation and N fertilization with 225 kg hm-2 could improve irrigation water use efficiency and thereby reduce potential N leaching on sandy farmland.