Abstract:Crude extracts of 44 maize inbred seeds were treated under different temperatures, i. e. 50, 55, 60, 65 and 70℃, in order to determine their heat sensitivity of esterase isozymes. The results showed large discrepancy of heat sensitivity of anodic esterase isozymes between different or same relative mobility bands of isozyme, but similar inactivating temperature (65℃) of the cathodic ones for different inbreds. The heat sensitivity of isozymes for inbreds may be adopted in the identification of variation and purity of inbred and hybrid seeds of maize.