Field-scale bioremediation of oily sludge on prepared beds was studied at the Shengli Oilfield in North China. Effects of addition of manure or soil conditioners (coarse sand and sawdust), inoculation of hydrocarbon degrading bacteria, and setting up greenhouses on oil and grease removal rate were evaluated. After 230 days of bioremediation, oil and grease content fell by 31.5~41.8 g kg^-1 dry sludge in treated plots, indicating a removal rate ranging from of 27.5% to 46.3% compared with that in the control plot, being only 15.1%. Addition of manure or soil conditioners and setting up of greenhouses significantly increased the removal rate (p < 0.05）. Moreover, the physic-chemical properties of the sludge in all treatment plots improved significantly after bioremediation. Microbial biomass in sludge and community-level physiological profiling (CLPP） analyzed using BIOLOG microplates were also studied. Total petroleum hydrocarbon（TPH）degraders and polycyclic aromatic hydrocarbon (PAH) degraders increased in all treated oily sludge. The activity of sludge microbial communities, characterized by average well color development (AWCD) value and Shannon diversity index, increased markedly in the treatment plots compared with that in the control.