The invention discloses a steam and power dual-power-drive fan structure. The problems that a fan drive structure is complex, single gas source drive or motor drive is adopted, at most of time, normalrunning needs cannot be met, and normal production is affected are solved. Two permanent magnet couplings are selected according to the actual industry and mining, when the permanent magnet couplingswork, a rotating gear drives a pushing disc to rotate, a pushing convex strip slides over a convex block from thin to thick, a sliding sleeve and a shaft sleeve are pushed to move in the direction away from the pushing disc, a permanent magnet disc gets close to a conductor disc, the air gap between the conductor disc and the permanent magnet disc is reduced, a steam turbine output shaft or electric motor output shaft can drive a fan rotating shaft to rotate, and an air outlet of the fan begins to output air. Through control over the gear turning angle, the air gap is controlled, engaging anddisengaging of the permanent magnet couplings and magnitude adjusting of output torque can be achieved, and due to a ratchet wheel, ratchets and a pawl, gear self locking is achieved.