The invention discloses a single-stage, multi-stage and variable-stage 
rotational flow air floatation oil-containing 
sewage treatment device, which comprises an outer shell comprising all stages of cylinder bodies, an upper seal head and a lower seal head, an inlet and outlet pipeline part comprising all stages of overflow pipes, all stages of 
reflux pipes, an underflow 
pipe and a central verticalpipe, and an internal structure comprising all stages of water distribution pipes, all stages of flow guide plates, annular channels and 
treated water collecting plates, wherein the first-stage overflow 
pipe is positioned at the top of the upper seal head, other overflow pipes are positioned on the upper side surfaces of various stages of the cylinder bodies, the underflow 
pipe is positioned at the lower seal head, various stages of the 
reflux pipes penetrate through various stages of the cylinder bodies and are communicated with various stages of the annular channels, the central vertical pipe is located on the axis of the cylinder bodies and penetrates through the lower seal head, the annular channels and various stages of the cylinder bodies, the first-stage water distribution pipe ispositioned at the top of the central vertical pipe, other water distribution pipes are positioned at the bottoms of the annular channels, various stages of the flow guide plates spirally incline upwards and are fixed on the inner walls of various stages of the cylinder bodies, and the 
treated water collecting plate is positioned between the two cylinder bodies. The device of the invention is compact in structure, easy and convenient to operate, wide in applicability and good in oil removal effect, wherein the single-body multi-stage design meets the requirements of different 
effluent qualitiesand treatment capacities.