Abstract: In order to investigate the heat resistance of Corylus heterophylla× Corylus avellana hybrid hazels, the relative electric conductivity (REC) of 13 varieties were measured under heat stress with 5 different levels: 30℃(CK), 35℃, 40℃, 45℃ and 50℃. The logistic equation was constructed based on the relationship between cell injured rate and temperature. The heat tolerance of the 13 varieties was evaluated by LT₅₀ and clustering analysis. The results showed that: (1) with the increasing of temperature, the rates of injured cell of the 13 varieties all rise to varying degrees, the extent of injure was: 12^#＜7^#＜26^#＜8^#＜3^#＜24^#＜6^#＜2^#＜1^#＜27^#＜30^#＜29^#＜28^#; (2) the inflection point of logistic equation suggested that the limit high temperature of the 13 varieties was from 39.29℃ to 47.02℃, the LT₅₀ was the highest in 12^# and the lowest in 28^#; (3) the 13 varieties were clustered into 3 branches: 1^#, 27^#, 28^#, 29^#, 30^# belonged to the first branch, 2^#, 3^#, 6^#, 8^#, 7^#, 24^#, 26^# belonged to the second branch and 12^# belonged to last branch. These results suggested that the heat threshold of the 13 varieties were from 39.29℃ to 47.02 ℃, 12^# had the highest heat tolerance, 1^#, 27^#, 28^# ,29^#, 30^# had a poor heat resistance and 2^#, 3^#, 6^#, 8^#, 7^#, 24^#, 26^# performed general in heat resistance.