Oxygen delignifi cation at atmospheric pressure and pressured of alkaline pulp after the hydrogen peroxide bleaching were discussed. The effect of xylanase pretreatment and polycarboxylic stabilizer on the peroxide bleaching were investgated especially. The results showed that pretreatment could improve the whiteness of pulp and the bleach ability of conventional hydrogen peroxide bleaching. Polycarboxylic stablizer could replace sodium silicate as a stabilizer of hydrogen peroxide bleaching agent. In addit...