Water and nitrogen(N) are generally two of the most important factors in determining the crop productivity. Proper water and N managements are prerequisites for agriculture sustainable development in arid areas. Field experiments were conducted to study the responses of water productivity for crop yield(WP_(Y-ET)) and final biomass(WP_(B-ET)) of film-mulched hybrid maize seed production to different irrigation and N treatments in the Hexi Corridor, Northwest China during April to September in 2013 and also during April to September in 2014. Three irrigation levels(70%–65%, 60%–55%, and 50%–45% of the field capacity) combined with three N rates(500, 400, and 300 kg N/hm~2) were tested in 2013. The N treatments were adjusted to 500, 300, and 100 kg N/hm~2 in 2014. Results showed that the responses of WP_(Y-ET) and WP_(B-ET) to different irrigation amounts were different. WP_(Y-ET) was significantly reduced by lowering irrigation amounts while WP_(B-ET) stayed relatively insensitive to irrigation amounts. However, WP_(Y-ET) and WP_(B-ET) behaved consistently when subjected to different N treatments. There was a slight effect of reducing N input from 500 to 300 kg/hm~2 on the WP_(Y-ET) and WP_(B-ET), however, when reducing N input to 100 kg/hm~2, the values of WP_(Y-ET) and WP_(B-ET) were significantly reduced. Water is the primary factor and N is the secondary factor in determining both yield(Y) and final biomass(B). Partial factor productivity from applied N(PFP_N) was the maximum under the higher irrigation level and in lower N rate(100–300 kg N/hm~2) in both years(2013 and 2014). Lowering the irrigation amount significantly reduced evapotranspiration(ET), but ET did not vary with different N rates(100–500 kg N/hm~2). Both Y and B had robust linear relationships with ET, but the correlation between B and ET(R~2=0.8588) was much better than that between Y and ET(R~2=0.6062). When ET increased, WP_(Y-ET) linearly increased and WP_(B-ET) decreased. Taking the indices of Y, B, WP_(Y-ET), WP_(B-ET) and PFP_N into account, a higher irrigation level(70%–65% of the field capacity) and a lower N rate(100–300 kg N/hm~2) are recommended to be a proper irrigation and N application strategy for plastic film-mulched hybrid maize seed production in arid Northwest China. Water and nitrogen (N) are generally two of the most important factors in determining the crop productivity. Proper water and N managements are prerequisites for agriculture sustainable development in arid areas. Field experiments were conducted to study the responses of water productivity for crop yield ( WP_ (Y-ET)) and final biomass (WP_ (B-ET)) of film-mulched hybrid maize seed production to different irrigation and N treatments in the Hexi Corridor, Northwest China during April to September in 2013 and also during April to September in 2014. Three irrigation levels (70% -65%, 60% -55%, and 50% -45% of the field capacity) combined with three N rates (500, 400, and 300 kg N / were tested in 2013. The N treatments were adjusted to 500, 300, and 100 kg N / hm ~ 2 in 2014. Results showed that the responses of WP_ (Y-ET) and WP_ (B-ET) to different irrigation works were WP_ (Y-ET) was significantly reduced by lowering irrigation higher while WP_ (B-ET) stayed relatively insensitive However, WP_ (Y-ET) and WP_ (B-ET) behaved consistently when subjected to different N treatments. There was a slight effect of reducing N input from 500 to 300 kg / hm ~ 2 on the WP_ ( However, when reducing N input to 100 kg / hm ~ 2, the values ​​of WP_ (Y-ET) and WP_ (B-ET) were significantly reduced. Water is the primary factor and N is the secondary factor in determining both yield (Y) and final biomass (B). Partial factor productivity from applied N (PFP_N) was the maximum under the higher irrigation level and in lower N rate (100-300 kg N / Lowering the irrigation amount significantly reduced evapotranspiration (ET), but ET did not vary with different N rates (100-500 kg N / hm ~ 2). Both Y and B had When the linear relationship between ET and WP (Y-ET) was linearly increased and then the correlation between B and ET (R ~ 2 = 0.8588) was much better than that between Y and ET WP_ (B-ET) decreased. Taking the indices ofWP_ (B-ET) and PFP_N into account, a higher irrigation level (70% -65% of the field capacity) and a lower N rate (100-300 kg N / hm ~ 2) are recommended to be a proper irrigation and N application strategy for plastic film-mulched hybrid maize seed production in arid Northwest China.