Abstract: Studies on bioremediation of PAHs contaminated soil were carried out using bio slurry reactor process.Phenanthrene (PHE) and pyrene (PY) were chosen as the test pollutants.The results showed that the physical and chemical properties of the pollutants were key factor affecting the bio remedying possibility of PAHs in soil.PAHs with less benzene rings and lower molecule weight were easier to be biodegraded.So,phenanthrene had higher bio remedying possibility than pyrene.Temperature and airflow were important control factors in bio slurry reactor process. In this research,the optimized parameters were operating temperature as 20～30℃,ratio between water and soil as 2:1,airflow as 8 L·h^-1·L^-1,and the inoculating amount as 50 g·kg^-1.