Mechanical pulping is a kind of high yield pulping that comes with the comprehensive utilization of plant material. Mechanical pulp has lots of benefits, such as simple process, low pollution, good bulkiness, fine stiffness, excellent optical performance and good printability. However, it also has disadvantages of lower paper physical strength and higher refining energy. In this paper, AU-MTPE90 enzyme and acid xylanase were used to modify the masson pine mechanical pulp before refining. The effects of modification on the shape parameters of masson pine mechanical pulp fiber and pulp properties were studied. The results showed that after modified by AU-MTPE90 enzyme and acid xylanase，the drainability of the refined pulp increased, the average fiber length increased and the fines percent decreased. The curl index and kink index increased slightly after modified by AU-MTPE90 enzyme，while the kink index decreased after modified by xylanase.