In this research, thermal and catalytic pyrolysis and the amount of liquid product obtained from pyrolysis and its composition have been considered. In pyrolysis of each polymer, the amount of liquid product was increased by performing several optimization steps on the reactor. According to studies, among the three catalysts used, the FCC catalyst produces the most liquid product and the HZSM-5 catalyst releases most of the product as gas due to the small pore size. By gas chromatography test, the percentage of liquid product components, aromatic, olefin, paraffin and naphthenic in the product were obtained and also liquid product components were obtained based on the number of carbons. The results of gas chromatography test show that a significant percentage of the product in pyrolysis with FCC catalyst is olefins. Evaluation can be said that in pyrolysis of rubbers (polybutadiene rubber and styrene butadiene rubber) due to the presence of many double bonds in their structure and the formation of many radicals during pyrolysis, a pyrolysis process will be multi-stage and unlike plastic pyrolysis. The hydrocarbon liquid product is extracted separately and in several stages. The trend of temperature changes in pyrolysis of tires is also increasing and decreasing.