| Shiyang River Basin lies in the east of Gansu Hexi, which is continental dry climate, ecological environment is very poor. Surface water is shortage and groundwater is over exploited. Maintainable development of agriculture depends on rational exploitation of water resource; water-saving irrigation is one of main measures under the condition of water shortage. The experiment was conducted in the experimental station of Wuwei Desert Park, we laid emphases on the growth, photosynthesis characteristic, leaf water potential, yield and water use efficiency of summer maize under the condition of different water and nitrogen. Factor was supplied by five: nitrogen fertilizer (A), seeding irrigation (B), jointing irrigation(C), heading irrigation (D), filling irrigation (E). Four nitrogen levels: 75kgN/hm2 (1), 150kgN/hm2 (2), 225kgN/hm2 (3), 300kgN/hm2 (4). Four water levels: 337m3/hm2 (1), 675m3/hm2(2), 1012m3/hm2(3), 1350m3/hm2(4). The orthogonal portfolio was used in the experiment. Nitrogen fertilizer was fertilized one time before sowing, Phosphorus fertilizer (calcium superphosphate) was fertilized by 560kg/hm2 in each district. The district area was twenty square metres; the experiment included a total of 32 districts. By study of one growth season, the result showed that nitrogen fetilizer was the the key effect factor of corn seedling leaf area and the plant height, the most appropriate amount of nitrogen was 75 kgN/hm2, demand for water and nutrients was small in corn seedling, effect of appropriate water lack on the plant growth was not great, amount of 75 kgN/hm2 could meet its growth need, excessive nitrogen fetilizer may burned seedlings, high nitrogen and full water was not conducive to maize growth. The ideal combination of promoting the corn seedlings growth was A2B2.Nitrogen fertilizer amount impacted on the corn roots growth reached a significant level. The seedling stage irrigation, jointing stage irrigation, tasselling stage irrigation, filling stage irrigation impacted on corn roots growth did not reach significant level. Compared to local nitrogen fertilizer level, the roots of A3 level, A2 level, and A1 level were reduced by 4%, 13.4%, and 31.3% respectively, Compared with the A4 level, nitrogen amount of A3 level was decreased by 75kgN/hm2, and root weight only decreased by 4%.The corn root weight was largest when seedling irrigation was A3, and it was minimum when seedling irrigation was A1.Nitrogen fertilizer amount and seeding irrigation impacted on the corn roots growth reached a significant level. Corn photosynthetic rate increased with the increasing of nitrogen and irrigation.The most important factor of effect on corn yield was nitrogen fertilizer amount, Effect of factors on the corn yield was different , the ranking followed by A>D>B>C>E, all factors impacted on the corn yield reached a significant level, compared to the A4( local nitrogen fertilizer level), the nitrogen rate of A3, A2, A1 were reduced by 25%,50%,75%;and corn yield was reduced by 6.9%, 12%, 34.8%.the proposed combination model was that: nitrogen fertilizer amount was 225kg/hm2, seedling irrigation was 1012m3/hm2,jointing stage irrigation was 1350m3/hm2, tasselling stage irrigation was 1012m3/hm2, filling stage irrigation was 337m3/hm2.The most important factor of affecting corn nitrogen water use efficiency was nitrogen rate, followed by the jointing stage irrigation, the factors order of affecting the corn water use efficiency(WUE)was A>C>B>D>E, Optimum combination of obtaining maize WUE was A4B3C2D3E1.NO3--N content of 0-100cm soil profile increased with increasing of nitrogen rate. NO3--N content of high-nitrogen treatment were significantly higher than that of other treatment. In 10-100cm soil profile, NO3--N content of lowest nitrogen and low nitrogen treatment didn't obviously change; In 040cm and 60～100cm soil profile,NO3--N of moderate nitrogen and high nitrogen treatment accumulated obviously in 40 60cm soil profile slightly.
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