The invention relates to a double micro-treatment technology used for treating oilfield produced water and mainly solves the problems that an existing treatment technology which can meet oilfield low-permeability oil layer reinjection water quality control index requirement is relatively complex and treated water quality can not reach the standard stably. The double micro-treatment technology is characterized by comprising the following steps: (1) enabling oily produced water to enter a micro-rotational flow flotation device, and carrying out oil-water separation; (2) enabling effluent treated by the micro-rotational flow flotation device to enter a buffer tank 1 and a micro-filtration device, and after effluent of the micro filtration device meets the oilfield reinjection water quality control index requirement, enabling the effluent to enter an outer water conveying tank; (3) lifting water in the outer water conveying tank, carrying out back washing on a filter material in the micro filtration device after one filtration period, and regenerating the filter material; and (4) enabling back washing sewage discharged by the micro filtration device to sequentially enter a buffer tank 2 and the micro-rotational flow flotation device to be retreated. The double micro-treatment technology provided by the invention can meet the oilfield low-permeability or extralow-permeability oil layer reinjection water quality control index requirement.