A water absorbent wood hydrogel was prepared with the wood and acrylamide using glutaraldehyde as crosslinker. The structure of wood-based hydrogel was charactered by FTIR spectra. The monomer ratio, the amount of glutaraldehyde, the behavior of pH-sensitivity and salt-sensitivity of the wood hydrogel were studied in this paper. The results are as follows: The water absorption and grafting yield of wood-based hydrogel decreased with the increasing of wood content. The water absorption of wood-based hydrogel decreased with the crosslinker content increasing, the grafting yield increases with the crosslinker content increasing. The water absorption of wood-based hydrogel has strong sensitivity in pH value of 3.0 ~ 11.0 solution. At acidic and alkaline larger environment, the hydrogel shows a larger water absorption, and the smallest swelling ratio was obtained in pH7.0 buffer solution. The wood-based hydrogel shows stable behavior in different concentrations of sodium chloride solution.