The invention provides a rotary mop washing spin dryer with a self-locking shaft-free lifting lateral axial column cylinder, wherein a rotary basket, a rotary basket support and a rotary basket lifting self-locking mechanism are disposed in a washing bucket. The spin dryer is characterized in that the lifting self-locking mechanism is designed to have a cylindrical self-locking slide block rotary groove which is coaxial with the rotary basket and a tube-shaped self-locking slide block on the washing bucket inner wall; an upper gear ring and a lower gear ring are disposed on the upper and lower ends of the inner side of the self-locking slide block tube body; drive teeth are disposed on the upper gear ring; brake teeth, slide groove guide teeth and a brake rack slide groove are disposed on the lower gear ring; through upward lifting and pressing of the rotary basket, a brake rack on the rotary basket support can be switched between the brake teeth and the slide groove guide teeth, lifting control of the rotary basket can be achieved, and whole courses including washing and spin-drying of the mop can be completed in one bucket through hand lifting and pressing; mop strips are overhung in the rotary basket and the rotary basket has a hollow bottom, so that the mop can be washed more quickly and thoroughly; and an anti-sway bearing is added to the rotary basket, so that the spin dryer has higher efficiency and a longer service life.