To investigate the effects of organic fertilizers and other nitrogen replacements for chemical fertilizers under different nitrogen application rates on the growth, yield and water-fertilizer use efficiency of spring maize in the dry zone of northern Shaanxi, multiple regression analysis and three-dimensional fitting models were used to establishing an optimal nitrogen management model for spring maize cultivation in northern Shaanxi. In this experiment, three nitrogen application levels were (N1: 240 kg/hm2, N2: 180 kg/hm2 and N3: 120 kg/hm2) and five organic fertilizers and other nitrogen replacements for chemical fertilizers ratios were (R0: 100% fertilizer nitrogen, R12.5: 12.5% organic fertilizer nitrogen + 87.5% chemical fertilizer nitrogen, R25: 25% organic fertilizer nitrogen + 75% chemical fertilizer nitrogen, R37.5: 37.5% organic fertilizer N + 62.5% chemical fertilizer N and R50: 50% organic fertilizer N + 50% chemical fertilizer N), a total of 15 treatments. During the main reproductive period of spring maize, spring maize growth and yield and yield components were measured, and water consumption (ET), water use efficiency (WUE), nitrogen fertilizer partial productivity (NPFP) and economic benefits were calculated. The results showed that the ????????????? Logistic function had a high fit for dry matter accumulation in spring maize, the R12.5 treatment delayed the start, the end and the appearance of the maximum value of the period of rapid dry matter accumulation, and the N2 treatment enhanced the maximum daily growth rate of dry matter accumulation. Nitrogen application and replacement ratio significantly affected dry matter accumulation, yield and components, ET, NPFP and economic efficiency of spring maize (P<0.05), and the interaction significantly affected ear length, ear coarse and ET (P<0.05). The average dry matter accumulation, yield, ET, and net income of N2 treatment were higher than that of N1 and N3 treatment 5.58 and 15.80%, 4.25% and 16.76%, 4.96% and 3.41%, 8.76% and 29.42%, respectively. R25 treatment significantly enhanced dry matter accumulation, yield and components, ET, WUE, NPFP, net income and input/output. WUE continued to increase with increasing N application while NPFP continued to decrease. Treatment N2R25 had the highest dry matter accumulation and ET, and treatment N2R37.5 had the highest yield, net income and input/output. Spring maize yield was significantly and positively correlated with dry matter accumulation, ET, WUE, net income and input/output. Taking into account the dry matter accumulation, yield, WUE and net income of spring maize, the nitrogen fertilizer management was optimized, and the nitrogen application rate and replacement ratio range were 160~230 kg/hm2 and 8~38%, respectively, spring maize dry matter accumulation, yield, WUE and net income can all reach more than 95% of the optimal value while the NPFP under the this combined treatment was 66.68 ~ 93.98 kg/kg.