Moisture absorption mechanism of magnesite bonded wood wool panel(MWWP) and measures generally taken to lower its hygroscopicity were reviewed. Three methods were then experimented to improve the dimensional stability of the panel, including adjustment of the molar ratio of raw materials, addition of additives and optimization of the curing method. The results show that satisfying dimensional stability can be achieved when the molar ratio of MgO to MgCl2 is 5︰1, the No.2 composite additive(aluminum powder+NH4H2PO4 +ferric alum) is used and a constant temperature and humidity treatment is applied in the first stage of conditioning.