The kinetic features of the process of delignification in green liquor (GL) pretreatment kraft pulping were investigated in this study. GL pretreatment can accelerate pulping by providing a faster delignification rate at the onset of the bulk delignification stage of pulping. In addition, GL pretreatment increases the efficiency of the chemical reactions occurring during the pulping process. A good correlation between chemical performance and lignin removal was established for the GL-modified pulping process. The pulping chemicals were mainly consumed during bulk delignification, and the relative efficiency of reaction for the hydrosulfide and hydroxide anions for delignification were 2 and 1.6 times higher, respectively, as compared to conventional kraft pulping.