Hydrogel polymers were prepared via graft polymerization of acrylamide (AAm) onto chitosan (CTS) backbone in the presence of methylene bisacrylamide (MBA) as cross-linker and ammonium persulfate (APS) as an initiator. Optimizing the crosslinking graft reaction of AAm onto CTS was studied by varying the concentration of CTS and MBA cross-linker and discussing the effect of these conditions on the gel fraction and the grafting parameters. The grafting parameters; grafting percentage (%GP), grafting efficiency (%GE), Add-on (%A) and homopolymer (%H) were studied as a function of the chitosan and the cross-linker concentrations. Also the swelling properties of the prepared hydrogel were examined. In this research, the simple second order kinetic model proposed by Schott has been carried out to describe the swelling mechanism. The effect of the grafting reaction on the thermal properties of the chitosan was also investigated by the thermal gravimetric analysis (TGA). The structure of the prepared hydrogel polymer was confirmed by FT-IR spectra. The porous structure of the hydrogel was observed by the Scanning Electron Microscope (SEM) and also the elemental composition of the prepared hydrogel was identified by using the energy dispersive X-ray (EDX).