Abstract: Experiments are carried out on the irradiation of solutions of poly-vinyl alcohol (PVA) and polyacrylamide (PAM) by gamma rays. Effects of pH, solvents and additives on PVA and PAM solutions by γ-ray irradiation are studied. When aqueous solutions of the polymers are irradiated, the gelation doses vary with different pH values. The gelation doses increase when radical scavenger is added, but there is no apparent effect when hydrated electron scavenger is added. Experiment results show that indirect action plays an important role on the irradiation crosslinkng of polymer solutions.