Abstract: In order to study the response of different maize genotypes to low nitrogen stress, and select the low nitrogen-tolerant maize genotypes to achieve higher yields under low nitrogen conditions, 41 hybrids were tested with normal and reduced nitrogen rates.The effects of reduced nitrogen application on traits of morphology, photosynthesis and grain yield were investigated, and the membership function analysis and comprehensive coefficient method were used to evaluate their tolerance to low nitrogen steress. The results show that most agronomic traits of the hybrids tested become worse under low nitrogen stress. Compared with normal nitrogen application, the average of phenotypic traits decreases by 5.5% - 18.0%; while the average length of bald ear tip increases by 54.7% when nitrogen application rate is reduced, and the coefficient of variation (CV) between genotypes is 31.5% - 65.2%. Fourteen out of 41 hybrids are classified as strong low nitrogen tolerance; and among the 14 hybrids, six hybrids have been commercially released and four hybrids are under approval, accounting for 71.4%. There are genetic resources available for low nitrogen tolerance, and released varieties exhibit obvious trend to tolerate low nitrogen.