Abstract: The paper probes into the thermal decomposition characteristics and swelling properties of scrapped bicycle tires and the automobile one sin detail. The kinetics of the tires' thermal decomposition process was studied by thermal gravimetric analysis to obtain the decomposition characteristics. The results showed that, due to different compositions, the two kinds of tires differed considerably in thermogravimetric curves, and that the process conformed to the first-order kinetic model. In the temperature range of 230~320 ℃, the thermal decomposition activation energies of the scrapped automobile tires and the bicycle ones were both about 25 kJ/mol. In the temperature range of 350~450 ℃, the activation energies were 80.5 kJ/mol and 49.1 kJ/mol, respectively. The effects of benzene, ethyl acetate and carbon disulfide on the swelling performance of the scrapped tires in different sizes at different temperatures were investigated. The results showed that the swelling process didn't comply with the solubility parameter principle, while it conformed to a quasi-first-order kinetic model. The three organic solvents lowered the activation energy of the scrapped bicycle tires' swelling process, facilitating the process. According to the SEM analysis, the scrapped tires soaked in the solvents had more pores on their surface after they were dried, which was beneficial to improving the mass transfer effect.