To explore the mechanism of maize photosynthetic characteristics and yield composition under the synergistic conditions of water and fertilizer in the Yellow River irrigation area，so as to provide a theoretical basis for meeting the high quality and yield of crops in arid areas. The field experiment was carried out from 2019 to 2020，and a two-factor split plot experimental design was adopted. The main plot was nitrogen application rate，which was 30% nitrogen reduction(N0)and conventional nitrogen application(N1)，and the secondary plot was drip irrigation amount，which was 30% drip irrigation reduction(W0)，conventional water drop(W1)and 30% drip irrigation increase(W2)，respectively. The photosynthetic characteristics and yield of maize in key growth period were analysed. The results showed that nitrogen application rate and drip irrigation rate had significant effects on leaf SPAD value，net photosynthetic rate，ABS/RC，Fv/Fm，Fv/F0，PI，yield and yield components. The highest average yield in 2 years was N0W2 treatment. Under the same nitrogen application rate and different drip irrigation rate，the SPAD value and net photosynthetic rate of leaves were significantly different，and increased with the increase of drip irrigation amount，but N0W2 and N1W2 had no significant difference. Under different water and nitrogen treatments for two years，LAI increased first and then decreased with the progress of growth，and reached the maximum value at tasseling stage. Fv/Fm，Fv/F0，ABS/RC and PI increased first and then decreased with the growth period，and the effect of drip irrigation was greater than that of nitrogen application. Under the same nitrogen application rate，the fluorescence parameters increased with the increase of drip irrigation rate. Under the drip irrigation rate of W2，there was no significant difference in Fv/Fm，ABS/RC，PI between N0 treatment and N1 treatment in the late growth stage，and Fv/F0 was significantly lower than that of N1 treatment，indicating that appropriate nitrogen application could increase heat dissipation and reduce the damage of high temperature to leaves while maintaining the captured light energy. The integrated mode of water and fertilizer combined with water and nitrogen treatments(nitrogen application rate of 292 kg/hm² and irrigation amount of 4290 m3/hm² in the whole growth period)in Ningxia Yellow River irrigation area can improve maize yield and nitrogen utilization rate，and provide theoretical support and technical guidance for local maize high-yield，high-quality and efficient cultivation and efficient utilization of water and fertilizer.