Abstract: The degradation of PAHs-contaminated soil from a coke plant in Beijing by combined ozonation pretreatment and bioremediation was studied through batch experiments. The results revealed that the accumulative amount of PAHs degradation by ozonation increased with time, while the degradation rate decreased. Pretreated with ozone concentrations of 0.79,1.74, and 4.50 mg/L respectively, total degradations of PAHs were 11.01%, 32.48% and 34.65% in the first 5 minutes, and slowly accumulated up to 39.58%, 52.84% and 53.79% after 60 minutes. However, the numbers of microbes decreased from 3.07×10⁸ to 1.73×10⁶,1.02×10⁵ and 1.49×10³ CFU/g, respectively. Pretreated with ozone concentration at 1.74 mg/L for 5 and 10 minutes followed by biodegradation for a week with and without LB cell culture, PAHs decreased about 68.93% and 63.32% with LB cell culture, about 35.34% and 24.33% higher than the degradation rates without LB cell culture. Pretreated with ozone concentration at 1.74 mg/L for 5 minutes and followed by biodegradation for 4 weeks with LB cell culture and saponin, PAHs degradation was 93.26%, improved by 7.00% compared with only LB cell culture added. The conclusion is that combined pre-ozonation and bioremediation can significantly enhance biodegradation rate of PAHs in soil.