The invention belongs to the technical field of oil field environmental protection, and relates to a microbiological treatment technology for oil-containing silt in oil field and a processing system thereof. The method comprises seven steps of homogeneity detection, floating oil recovery, sewage discharge, microbe degradation, dehydration treatment, standard discharge of oil-containing silt, sewage purifying, and purified water reutilization, and the microbiological treatment system comprises a feeding apparatus, a microbiological treatment apparatus, a dehydrated apparatus, a sewage treatmentapparatus, a filtering apparatus, a water storage apparatus, a circulating pump, a crude oil retrieving apparatus, a control apparatus, and a circulating pump. The system has the advantages of simpleprocessing flow and short processing period, greatly recovers crude oil in the oil-containing silt, realizes harmlessness processing of the oil-containing silt, and has low cost, sewage in the system can be recycled, and a purpose of resourcing and harmlessness of the system can be achieved.