Abstract: Taking alfalfa(Medicago sativa) as test plant and with pollutant content level,specific bacteria,fungi and organic fertilizer as control factors,the plant bioremediation of polycyclic aromatic hydrocarbons (PAHs) and mineral oil contaminated soil was conducted.The degradation rate of PAHs and mineral oil was positively correlated with the content of organic fertilizer in soil.Increasing the content of organic fertilizer by 5% would increase the degradation rate of mineral oil by 176～256%,PAHs by 9%.On the presence of plants,the degradation ability of soil microbes was enhanced,with the average degradation rate of total PAHs 20～47%higher than that of control.The applied fungi improved in some degree the degradation of PAHs and mineral oil.Fungi obviously enhanced the degradation rate of fluoranthrene,pyrene and benzo(a)anthracene/chrysene,while bacteria obviously increased the degradation rate of acenathene/fluorene,anthracene and benzo(a)fluoranthene/benzo(k)fluoranthrene.

Key words: Soil pollution Polycyclic aromatic hydrocarbons(PAHs), Bioremediation, Degradation rate