Starches from 6 botanical species varies greatly in molecular structures.The effects of their structure on the rate of α-amylase hydrolysis were studied.The results showed that the α-amylase hydrolysis rate of amylose was lower than that of amylopectin and amylose content was not the main factor affected α-amylase hydrolysis rate.Amylopectin had a greater impact on the rate of α-amylase hydrolysis.The correlation between the rate of α-amylase hydrolysis and amylopectin average chain length was significant.