Abstract: The waste corrugated paper was grinded to paper pulp, and used to prepare the foamed waste paper pulp/starch composites by injection molding foaming with starch, polyving akohol and foamer of azodicarbonamide-zinc oxide(AC-ZnO). The double-barrel capillary rheometer was used to research the influence of waste paper pulp content, mixed plasticizer of glycerol and dioctyl-phthalate(G-DOP) content, compatilizer of polyacrylic acid (EAA) content, foamer of AC-ZnO content and temperature on the rheological behavior of the composites melt. SEM was also used to observe the effect of different viscosity of melt on the cell morphologies. The results show that: the melt performs of the waste paper pulp/starch foam composites are pseudoplastic flow. The viscosity of melt is significantly reduced with the content of mixed plasticizer increasing, decreased with increasing of AC-ZnO content and increased with the content of the waste paper pulp and EAA increasing. The viscosity of melt is firstly decreased with the temperature rising, then increased. The number of cell increases and size of cell becomes smaller with the viscosity decreasing. When the viscosity is 900 Pa·s, cells happens to rupture and merge.