The invention discloses an automatic extruder filter screen replacing device capable of keeping continuous material flow. The automatic extruder filter screen replacing device comprises a flow channelswitching mechanism and a filter mesh replacing mechanism; the filter mesh replacing mechanism comprises a base, the base is provided with a protrusive gear ring portion, a fixing inner gear ring isarranged on the inner hole wall of the protrusive gear ring portion, a fixing outer gear ring is arranged on the outer cylindrical face, a first driving gear is arranged at the central axis of the base in a rotary driving mode, and at least n first planetary filter mesh frame units are rotatably and symmetrically arranged between the first driving gear and the fixing inner gear ring in a meshing mode; and the outer cylindrical face of the base is rotatably provided with a rotatable inner gear ring, and at least m second planetary filter mesh frame units are rotatably and symmetrically arrangedbetween the fixing outer gear ring and the rotatable inner gear ring in a meshing mode. According to the automatic extruder filter screen replacing device capable of keeping the continuous material flow, the two rings of planetary gear mechanisms concentrically rotating cooperate with the flow channel switching mechanism, therefore, automatic filter screen replacing is achieved, and meanwhile thematerial flow can continuously flow at the constant pressure and flow speed.