Polypropylene (PP) with biomass such as saw dust, rice husk, and corn cob were copyrolyzed in a fixed bed reactor at the temperatures of 450 degrees C, 500 degrees C, 550 degrees C, and 600 degrees C under nitrogen atmosphere. The effect of activated carbon as catalyst on pyrolysis liquid was also studied. The thermogravimetric behavior for two kinds of material was observed by thermogravimetric analysis. The gaseous products were analyzed by Gas Chromatography-Thermal Conductivity Detector (GC-TCD), Gas Chromatography-Flame Ionization Detector (GC-FID) for the blend of 50% PP, and 50% biomass. The copyrolysis liquids were investigated by Infrared Absorption Spectroscopy (IR), GC-MS, and liquid chromatography. The result showed that a suitable pyrolysis temperature was between 500 degrees C and 550 degrees C, and a fast heating rate for the reactor should be required. Fast carrier gas was beneficial to the formation of the aliphatic compounds. When the pyrolysis temperature reached 600 degrees C, C3H6 and H-2 were the main valuable gases, which were 20% and 10% (v/v), respectively. The occurrence of the activated carbon may improve the capability for the removal of the oxygen of pyrolysis liquid.