AbstractSoaking aqueous ammonia (SAA) pretreatment of corn stover was carried out at three temperatures (30, 50, and 70 ºC) and three concentrations of ammonia solution (5, 15, and 25 wt.%). The delignification kinetic model, based on three first-order reactions, was applied to describe the kinetic behavior of lignin removal from corn stover during SAA pretreatment. The first, second, and third terms were based on the initial, bulk, and residual phases of delignification, respectively. The results showed that the model fitted well with the data obtained from the experiments. The activation energies for the delignification reactions were estimated as 61.05 and 59.46 kJ/mol in the bulk and residual phases, respectively. Delignification selectivity increased with increasing reaction temperature.