The invention discloses an extruded foamed sheet and plate head. The extruded foamed sheet and plate head comprises an extruder material inlet pipeline, an upper sheet and plate channel mold, a lowersheet and plate channel mold, a sheet and plate channel side template and a mouth mold outlet, a polymer melt flowing cavity is limited by the extruder material inlet pipeline, the upper sheet and plate channel mold, the lower sheet and plate channel mold, the sheet and plate channel side template and the mouth mold outlet, the polymer melt flowing cavity comprises an inlet pipeline chamber, a shunting transition region, a melt steady flow region and a convergence region, and an expansion angle of 5-45 DEG is formed between the inner sidewall and the axial direction of the polymer melt flowingcavity from the boundary position of the shunting transition region and the stable flow region to the convergence region. The extruded foamed sheet and plate head has the advantages of production ofcreases reduced or eliminated polymer extruded foamed sheets and plates, improvement of the uniformity of the surface quality and the mechanical performances of the products, reduction of the defective index of the products, and increase of the production benefit.