Studying the role of hard wood pulp oxygen delignification of the use of peracetic acid(Pa) pretreatment combined with Surfactant AO. The experiment showed that when the peracetic acid dosage was 0.5%, pH was 6, the reaction time was 30min, the surfactant dosage was 0.2%, the pulp delignification rate increased by 13%, and the delignification selectivity also improved significantly. After QP bleaching treatment, the whiteness of enhanced oxygen delignification slurry reached 83.6%ISO, while the whiteness of conventional oxygen delignification pulp was only 73.5%ISO.