The invention discloses a coupler with a symmetrical spacing adjustment mechanism. The symmetrical spacing adjustment mechanism is simple in structure and convenient to control, and air gap spacing adjustment can be realized by only driving a bidirectional lead screw sleeve to rotate; according to different working conditions, a signal detected by a load end is taken as the reference, the air gapbetween two disks is adjusted through a control algorithm, so that closed loop control and energy conservation can be realized easily; by driving the bidirectional lead screw sleeve to rotate, a permanent magnetic rotor disk I and a permanent magnetic rotor disk II are adjusted to realize synchronous symmetrical air gap spacing adjustment, and relatively high adjustment precision and consistency is achieved; the symmetrical spacing adjustment mechanism is moved outwards to be separated from the permanent magnetic rotor disks, so that the coupler is more reliable in performance, the available area of the permanent magnetic rotor disks is enlarged, and power balance can be realized more easily; and an output shaft adopts a floating type structure, so that compared with the output shaft whichadopts an axial fixed type structure in the prior art, the output shaft is higher in flexibility, so that higher sensitivity in air gap spacing adjustment is achieved.