Grafting of cotton stalk pulp with methylmethacrylate monomer using a ceric salt redox system is carried out. The effect of different variables—for example, monomer dose, reaction time, reaction temperature, acid concentration, initiator concentration, and liquor ratio—are studied. The effect of the presence of different amounts of residual lignin in cotton stalks pulp on the grafting process is demonstrated. Residual lignin percentage in the pulp plays an important role in determining the grafting rate. A sharp decrease in the grafting rate is observed by increasing the residual lignin percent in pulp from 1.64% to 4.96%. As the residual lignin percentage in the pulp is increased to 12% in pulp, the grafting reaction is nearly stopped. Optimization of the grafting conditions is clarified.