In order to further study the mechanism of hydrolysis reactions to sugars using cornstalk on plasma, preliminary study of reactive process are carried out. Model compounds of cornstalk components are chosen and hydrolyzed on plasma. Activation energy of elementary reactions, which are single-molecule reactions, free radical reactions and bimolecular reactions, are calculated by bond energy percentage rules. Elementary reactions and preliminary reaction mechanism model, which cornstalk hydrolyzes to sugars on plasma are identified.