The invention discloses an air floatation-dynamic film coupling separation device suitable for thickened oil sewage treatment as well as a separation method. The device comprises a coagulation air floatation treatment system and a dynamic film separation system; the coagulation air floatation treatment system comprises a mixed reactor and an air floatation pool; the dynamic film separation systemcomprises a pre-coating film liquid storage tank, a dynamic film filter and a water producing tank. The method comprises the following steps: performing a mixed reaction between the thickened oil sewage and a medicament, introducing pressurized nitrogen, and removing a bubble-particle composite body from the liquid level of the mixed solution to obtain sewage subjected to primary oil removal and suspended material removal; performing microfiltration filtering on the sewage subjected to primary oil removal and suspended material removal by a hydrophilic metal base microfiltration dynamic film,and removing oil and suspended materials to obtain clean water; backwashing the hydrophilic metal base microfiltration dynamic film by using the clean water, regenerating the hydrophilic metal base microfiltration dynamic film and repeating the above steps to obtain the clean water. The treatment flow of the thickened oil sewage is short, the cost is low and secondary pollution is avoided.