Compared to middle oil and heavy oil, light oil has more extensive use in practice. Therefore, many factors that affect the light oil fraction of liquid produced during pyrolysis of waste tires were investigated with GC-MS, FT-ir, and chromatographic column as separated means. The results showed that carrier gas, flow rate, heating rate, and temperature all influence the percent of light oil. CO2 as carrier gas and fast flow rate can benefit to improve the yield of light oil, and fast heating rate cannot be favorable for the quality of oil. The components of the liquid composed of nearly 50% aromatic hydrocarbon, 19.06-24.66% alkanes, and distribution of polycyclic aromatic hydrocarbons (PAHs) as the function of temperature were also determined. Meanwhile, the depth of pyrolysis and relation of PAHs and possible reactions that occurred during pyrolysis were discussed.