A permanent-magnet coupling self-alignment protection device, comprising a first rotor and a second rotor respectively in fixed connection with a load shaft and a driving shaft, the first rotor and the second rotor being respectively mounted with permanent magnets that are mutually coupled to transmit torque, the first rotor and the second rotor are respectively configured with an inner conical surface and an outer conical surface that are coaxial and have mutually matching tapers; the device further comprises an axial adjustment mechanism for adjusting the relative axial position between the first rotor and the second rotor, wherein, the first rotor is an inner permanent-magnet rotor connected to the load shaft or the driving shaft, the inner conical surface is formed on the inner permanent-magnet rotor, the second rotor comprises an outer permanent-magnet rotor and an outer taper sleeve, the outer permanent-magnet rotor is connected to the driving shaft or the load shaft, the outer conical surface is formed on the outer permanent-magnet rotor, and the outer taper sleeve is sleeved on the outer permanent-magnet rotor, the axial adjustment mechanism is adapted for adjusting the relative axial position between the inner permanent-magnet rotor and the outer taper sleeve, characterized in that, the permanent magnets are mounted on a surface of the first rotor other than the inner conical surface thereof and a surface of the second rotor other than the outer conical surface thereof, the axial adjustment mechanism comprises an adjustment plate configured parallel to a rotary plate of the outer permanent-magnet rotor, the adjustment plate is in fixed connection with the outer taper sleeve, the adjustment plate is in threaded connection with the outer permanent-magnet rotor via a first screw bolt; the adjustment plate is also provided with a second screw bolt that is screwed therein, and an end portion of the second screw bolt is pressed against the rotary plate. the first rotor and the second rotor are respectively configured with an inner conical surface and an outer conical surface that are coaxial and have mutually matching tapers; the device further comprises an axial adjustment mechanism for adjusting the relative axial position between the first rotor and the second rotor, wherein, the first rotor is an inner permanent-magnet rotor connected to the load shaft or the driving shaft, the inner conical surface is formed on the inner permanent-magnet rotor, the second rotor comprises an outer permanent-magnet rotor and an outer taper sleeve, the outer permanent-magnet rotor is connected to the driving shaft or the load shaft, the outer conical surface is formed on the outer permanent-magnet rotor, and the outer taper sleeve is sleeved on the outer permanent-magnet rotor, the axial adjustment mechanism is adapted for adjusting the relative axial position between the inner permanent-magnet rotor and the outer taper sleeve, characterized in that, the permanent magnets are mounted on a surface of the first rotor other than the inner conical surface thereof and a surface of the second rotor other than the outer conical surface thereof, the axial adjustment mechanism comprises an adjustment plate configured parallel to a rotary plate of the outer permanent-magnet rotor, the adjustment plate is in fixed connection with the outer taper sleeve, the adjustment plate is in threaded connection with the outer permanent-magnet rotor via a first screw bolt; the adjustment plate is also provided with a second screw bolt that is screwed therein, and an end portion of the second screw bolt is pressed against the rotary plate.