Abstract: The distributions of hydrocarbon and non-hydrocarbon compounds as well as the method of dechlorination pretreatment of the tire top line oil were studied. The tire top line oil was accurately cut into 10 narrow fractions, then the elements, hydrocarbons, the main chloric components and the chlorine distributions in each narrow fraction were investigated by micro coulometry and GC-MS analysis. Alkali wash method was used for dechlorination pretreatment of the top line oil. The influence of reaction temperature, reaction time and NaOH solution to tire top line oil volume ratio was tested by orthogonal test. The results show that saturated hydrocarbon and chlorine content decreases along with the temperature rise of distillation range, while aromatics content decreases. The distribution of unsaturated hydrocarbon content is more uniform. The dechlorination rate is 59.70% at the optimized conditions: reaction temperature of 100 ℃, reaction time of 4 h, NaOH solution to tire top line oil volume ratio of 1.5:1.