The chemical Composition of Chinese red pine (Pinus massoniana) submerged in the Yellow Sea for more than 700 years has been examined. When compared to the recent wood, the marked chemical changes in the waterlogged wood is the higher amount of lignin with lesser amount of holocellulose and abnormally high ash content. In the heavily degraded samples, the degradation of cellulose is more severe than that of hemicellulose. However, hemicellulose is much more attacked than the cellulose at the initial stage of deterioration in the sea water. Chemical analysis suggests that the cellulolytic marine microorganisms, whether they are fungi or bacteria. can be regarded as the primary agents for the destruction of the archaeological woods submerged in the sea water.