The analysis on chemical components of BWAP indicated that the content of pentose in each fraction was about 21%;the ash content increased with the screen meshes,P 105 being more than 35% of whole pulp.BWAP of the fiber length more than 1.3 mm accounted for 24% and the length less than 0.4 mm was about 40%.The results of surface chemistry characteristics analysis proved that the carboxyl groups content in 100 g BWAP was about 9.3 mmol which was much higher than that in wood free pulp.The carboxyl groups content in P 105 and R 105 was higher than that in BWAP.The measurement of specific surface area showed that P 105 had 2.34 times of the whole pulp and 3.30 times that of R 28 .The Zeta potential pointed out that BWAP had a more strong potential than wood free pulp,the potential of R 28 was lower and the others were similar.