By means of microcosm experiments, we investigated the effects of sawdust on the remediation of fluoranthene and pyrene contaminated soil together with Mycobacterium flavescens (MC). The effects of sawdust size, added amount and origin sources on the remediation of fluoranthene contaminated soil with MC were investigated. The results showed that: sawdust could improve the remediation efficiency of MC on soils, including yellow-brown soil, black soil and red soil. The microbial communities of black soil and fluvo aquic soil had a good degradation effect on fluoranthene, and the low pH of red soil led to the addition of degradation bacteria MC could not degrade fluoranthene well.