Abstract: The authors calculated the superdelocalizabilities and charge densities of 14 model reative dyes and model reactive dye-cellulose compounds by the HMO and SCF-MO me- thods. Hydrolysis of such compounds has been discussed based on Klopman and Fukui's theories of superdelocalizability. The authors have proposed that, in the case of alkaline hydrolysis of reactive dyes and dyed materials, the activity be controlled by the interac- ting orbitals. Superdelocalizability is a good active index for hydrolysis of reactive dyes and dyed materials.