With phenanthrene and pyreneas as test pollutants,four control factors(inoculation amount,water soil ratio, air flux and temperature) were selected to study the microbiology degradation control of PAHs in bio slurry reactor.Results indicated that at the test concetration the optimum parameters for obtaining the maximum degradation rates for phenanthrene and pyrenene are 5%~10% in incubation amount,2∶1 for water/soil ratio,0 06~0 1m 3·h -1 for air,and 30℃ in temperature,degradation rate was the highest in this condition with the values 98 9% and 84 2% phenanthrene and pyrnene respectively on the 15th day.These parameters provide useful basis for large scale engineering to treat soil PAHs by means of bio slurry reactor.