Under the natural high temperature environment in summer of Xinjiang, taking the barren stalk, ear seed setting rate and relative seed setting rate as the main evaluation indexes, we coupled with the yield and main agronomic traits, to identify and evaluate the heat tolerance of 26 maize inbred lines for 2 consecutive years. Combined with the local high temperature and dry climate characteristics, we established a set of heat tolerance identification and evaluation system, which is helpful for heat tolerance improvement and breeding new varieties of maize in China. The results showed that: (1) there were great differences in the empty stem rate, ear setting rate, relative seed setting rate and heat tolerance of different maize genotypes. Among them, GW5F, GW4F, GW7F and PH6WC had the strongest heat tolerance. Under high temperature stress, the empty stem rate was the lowest, and the ear seed setting rate and relative seed setting rate were the highest; Secondly, 8 inbred lines such as PHBA6 and Xinzi 351 had better yield and comprehensive performance under high temperature stress. Other inbred lines were sensitive to high temperature. (2) High temperature stress led to a serious decline in maize ear traits. Ear weight, rows per ear and grains per row were most seriously affected. (3) The correlation between yield and main agronomic traits was quite different between years or materials, and the correlation between ear weight and yield was the highest. (4) Taking the relative seed setting rate as the main assessment criteria, the tested materials can be divided into two categories by hierarchical clustering. GW5F, PH6WC and GW4M were clustered into the first group. The second group contains three subgroups; Six inbred lines such as Ji 63 and Mo17 were clustered into the first subgroup; 6 inbred lines such as PHBA6 and LH82 were clustered into the second subgroup; 11 inbred lines such as Zheng 58 and Xinnongyu 6390M were clustered into the third subgroup. In summary, four inbred lines with extremely high temperature tolerance were identified, which can be used for basic research and genetic improvement of maize heat tolerance. 8 inbred lines with strong heat tolerance were mostly local inbred lines in Xinjiang, which have a wide genetic basis, adapt to the local high temperature, and were excellent heatresistant breeding materials.