The waste tire and the styrene-butadiene rubber were depolymerized in a supercritical tetrahydrofuran, respectively. TGA thermograms of the waste tire and residue were divided into two regions ; First, weight loss region by decomposition of the styrene-butadiene. Second, the region by decomposition of low molecular weight materials. The average molecular weight of both products from the styrene-butadiene rubber and the waste tires decreased, as process variables such as temperature, pressure and time incresed. So it was possible to depolymerize the styrene-butadiene rubber and the waste tires with low temperature process around 300 ℃ in supercritical fluid precess and recover oil with low molecular weight.