Abstract: In the present work, radiation-induced free radicals of cellulose were investigated. It was found that the radicals were very unstable in basic media and it is very important in radiation modification of cellulose. The effects of swelling agents (water, iso-propyl alcohol, benzene) on radiolysis of cellulose were studied. The results showed that the swelling agents had protective effects to a certain extent and the radiation degredation of cellulose in the swelling agents obeyed the Charlesby' s equation.