The crosslinking of initially non-hydrolyzed polyacrylamide with chromium in its +3 valence state was investigated in this work. IR spectra showed that the gelation occurred when the polyacrylamide was hydrolyzed, which implies that the gelation should take place at elevated temperature under neutral condition. The gelation process was monitored by means of viscosity measurement. The addition of acetic acid to the system might lead to the delay of gelation, owing to the synergistic effect of chelating with Cr(III) and acidity.