The water state in crosslinked chitosan/polyether semi-IPN(cr-CS/PE semi-IPN) hydrogels swollen in buffer solutions with various pH values was studied using differential scanning calorimetry (DSC). The results show that the total water content and the amount of bound water is related to the pH values of the swelling medium. The swelling kinetics of the hydrogel was investigated as well. The diffusion coefficient is correlated with the water state of the swollen hydrogel. It suggests that the change in the diffusion coefficient is related to the relative composition of bound water and nonbound water.