AbstractOxygen delignification of wheat straw soda pulp with the addition of anthraquinone (AQ) was conducted to evaluate the effects of AQ on pulp quality. The pulp yield, kappa number, intrinsic viscosity, and brightness were selected as the properties to optimize oxygen delignification. The optimal pulp was obtained via grey relational analysis with an alkali charge of 3%, oxygen pressure of 0.5 MPa at 120 °C for 85 min, and with 0.05% AQ. In contrast to conventional oxygen delignification, the addition of AQ produced pulp with a higher yield, and it did not generate other negative impacts on pulp kappa number, viscosity, and brightness. The reaction mechanism of AQ in oxygen delignification was different from that in alkali pulping.