The chemical comcomposition and water prehydrolysis of moso bamboo were studied to prepare high grade dissolving pulp. The results indicated that the moso bamboo was an appropriate none-wood material for great dissolving pulp goten as its high cellulose content. By single factor method, the optimum prehydrolysis conditions which were 150 degrees C, 120minutes and 1:8 of liquor-to-wood tatio, were obtained. Based on the optimum conditions, the yield was 90.35%, and the retention rate of cellulose, pentosan, acid accumulator insoluble lignin, and ash were respectively 96.30%, 88.22%, 88.13%, and 11.71%.