The waste corrugated paper was grinded to paper pulp first, and then the paper pulp was used to prepare the foamed waste paper pulp/high density polyethylene（HDPE）composites by compression molding with HDPE. The Rosand double-barrel capillary rhepmeter was used to research the influences of the blowing agent AC(Azodicarbonamide) content，waste paper pulp content，temperature and different blowing agent on the melt of the composites. Scanning electron microscopy（SEM）was also used to observe the effects of different contents of AC and waste paper pulp on the cell morphologies.The results showed that: when the shear rate up to 600 S-1，the melt performs of the foamed waste paper pulp/ HDPE composites were pseudoplastic flow, and turn up wall slip phenomenon. The viscosity of melt was significantly reduced with the content of AC increased, but it increased with the content of the waste paper pulp increased. When the shear rate reduced to 275 S-1 or below, the viscosity of melt reduced as the temperature riased; while when the shear rate went up to 275 S-1 or high, the viscosity of melt increased as the temperature riased. When the shear rate reduced to 325 S-1 or below, the melt of endothermic blowing agent （NaHCO3）showed the highest viscosity; when the shear rate went up to 325 S-1 or high, the melt of exothermic blowing agent AC shows the highest viscosity. The number of cell increased and size of cell became smaller with the AC content increased , but the number of cell reduced and the size of cell became larger with the content of waste paper pulp increased observing by SEM.
