Abstract:A field experiment was conducted with tow genotypes (ZD958 and XY335) as test material to investigate the effect of nitrogen and irrigation on the seed yield and use efficiency of irrigation and nitrogen, including copious irrigation (6 000 m3·hm-2,W6000), moderate stress irrigation(4 500 m3·hm-2,W4500) and severe stress irrigation(3 000 m3·hm-2,W3000),and three nitrogen levels, no nitrogen application (0 kg·hm-2,N0), moderate nitrogen application(225 kg·hm-2,N225) and relative to high nitrogen application(450 kg·hm-2,N450),the yield and yield component factor of seed, soil moisture content and soil NO3--N in 0-100cm soil layer depth was investigated. The result showed that no significant difference between irrigation rates. The yields of treatments under nitrogen applied were significantly greater than that of no nitrogen applied, the seed yield of XY335 was better than that of ZD958, and the yield of treatment W4500N450 is highest for 11 147 kg·hm-2, while 100-grain weight of XY335 seed was significantly greater than that of ZD958. The yield component factors of ZD958 seed in nitrogen applied was greater than those of no nitrogen applied. Soil NO3--N accumulation in 0-100cm soil layer depth under moderate stress irrigation was significant higher than other two irrigation levels. The water use efficiency, partial productivity of nitrogen, agronomic efficiency under moderate stress irrigation and moderate nitrogen application was better than other treatments. Therefore, in the present experiment, the optimal combination of irrigation and nitrogen rate is W4500N225 for seed production corn in Hexi, which has higher grain yield and use efficiency of water and nitrogen.