In order to explore the model of critical nitrogen dilution curve of maize under the integrated mode of drip irrigation and water fertilization, local maize main variety “Tianci 19” of Ningxia Hui Autonomous Region was used as the experimental material, and six nitrogen levels (0kg/hm2, 90kg/hm2, 180kg/hm2, 270kg/hm2, 360kg/hm2 and 450kg/hm2) were set, the dynamic changes of aboveground biomass and nitrogen accumulation in drip irrigation maize were studied, a critical nitrogen dilution curve model of maize was constructed, and a nitrogen absorption model and nitrogen accumulation deficit model were built on this basis to achieve rapid diagnosis of nitrogen nutrition status of drip irrigation maize. The results showed that the dry matter quality and nitrogen uptake of the aboveground drip irrigation were affected by the nitrogen application level, and it was increased with the progress of the growth process. The excessive or too low nitrogen accumulation was not conducive to the formation of yield, and the nitrogen of maize plants, the luxury consumption phenomenon existed. The critical nitrogen concentration, the highest and the lowest nitrogen concentrations of the drip irrigation maize can be expressed by the power function equation, and the average coefficient of determination R2 was 0.976, 0.903 and 0.941, respectively, which reached extremely significant level. The nitrogen uptake model and the nitrogen accumulation deficit model based on the critical nitrogen concentration were consistent with the results of nitrogen nutrition diagnosis during the growth period of drip irrigation maize, and the fitting curve of comprehensive nitrogen application rate and yield, recommending the nitrogen application rate of drip irrigation maize in Ningxia Yellow River Irrigation District as 270~311kg/hm2. The research result provided a theoretical reference for the precise fertilization and optimized nitrogen management of drip irrigation maize in Ningxia Yellow River Irrigation District.