The invention relates to a paper pulp screening machine in a rotary screen type, and specifically relates to a pressurized screen buffer device. The device comprises a cylindrical pressurized screen rotor; a shaft bush connected with a rotating shaft is arranged in an inner cavity of the pressurized screen rotor; the rotating shaft penetrates in the shaft bush; the shaft bush is fixedly connected with the pressurized screen rotor through an annular connecting plate; the annular connecting plate is of a dual-layer structure composed of an upper annular connecting plate and a lower annular connecting plate which are arranged along an axial direction at intervals. The device further comprises a flow-dividing mechanism, wherein the flow-dividing mechanism comprises a flow-dividing packet, a flow-dividing hose and a flow-dividing spherical head; the flow-dividing packet is communicated with water inlet holes, one end of the flow-dividing hose is communicated with the flow-dividing packet, and the other end of the flow-dividing hose is communicated with the flow-dividing spherical head, and the flow-dividing spherical ball is hinged with a water outlet spraying hole. The pressurized screen buffer device aims at providing a pressurized screen capable of quickly diluting the high concentration pulp region of the pressurized screen.