Immobilized with PVA, sodium alginate and activated carbon, both Zoogloea sp. and Fusarium sp. strains could degrade phenanthrene and pyrene efficiently. The optimal carrier was made of 100 rho.g-1 L PVA, 5 sodium alginate rho.g-1 L and 50 activated carbon rho.g-1 L. The degradation rates of phenanthrene and pyrene in 10 days were 87.48% and 75.34% by the immobilized bacterium, 37.04% and 20.85% higher than those by the free bacterium, and the rates in 15 days were 84.36% and 74.87% by the immobilized fungus, 5.35% and 11.23% higher than those by the free fungus.