The objectives were to enhance calculation accuracy of physiological parameters of photoresponse, and assess photosynthesis mechanism and characteristics of maize under fertigation of drip irrigation in Ningxia Yellow River Irrigation Area. Using Tianci-19 (TC19) as experiment materials, the photoresponse curves of spike leaves of maize were measured by Li-6400XT gas exchange system under six nitrogen rates at silking stage of maize from 2017 to 2018. The rectangular hyperbola modified model and other four kinds of common models were used to analyze photoresponse process of spike leaves of maize, with the aim of evaluating and selecting optimal model to calculate the photoresponse parameters of maize. The results showed that there were differences in the fitting accuracy of the four models, and the right angle hyperbolic, non-orthogonal hyperbola and exponential models had poor fit to the nitrogen-deficient (N0) photoresponse curve, and the rectangular hyperbola modified model had the highest fitting degree to each rate which was used as the optimal model to calculate the photoresponse parameters of maize at silking stage. The photosynthesis ability of maize was increased and then decreased with the increase of nitrogen rates. The photoresponse parameters (compensation point, light saturation point, maximum net photosynthesis rate, apparent quantum efficiency and dark respiration rate) of N4 (360kg/hm2) were all higher than those of other nitrogen rates, and there was a slight decreasing trend in N5 (450kg/hm2). The conclusions can be drawn that the rectangular hyperbola modified model can be used to calculate the photoresponse parameters of maize, so as to diagnose the nitrogen nutrition status, regulate the optimal nitrogen application rate, improve the photosynthetic capacity at silking stage, and enhance the yield of maize.