A reef wave power generation device does not occupy the space resource of a coast sand beach, a semispherical buoy moves up and down along with waves all the time during rising tide or falling tide ofsea water, a lower swing rod, an upper swing rod, a left connection arm and a right connection arm are driven to swing up and down, a drive shaft is driven to rotate alternately in the forward direction and the reverse direction, when the drive shaft rotates in the forward direction, a right overturn clutch is in a coupling state, a right cone gear is driven to rotate in the forward direction, the right cone gear drives a rear cone gear to rotate in the forward direction, at the moment, a left overturn clutch is in a disengaged state, a left cone gear idles in the reverse direction, forward rotation and reverse rotation of the drive shaft share the same principle, the rear cone gear keeps rotating in the forward direction all the time, the left cone gear and the right cone gear drive a front cone gear and the rear cone gear to accelerate for drive, balanced drive is achieved, three planetary gears drive an accelerating shaft to drive a flywheel and a columnar rotor to rotate at a highspeed through two-stage acceleration, inertia of the flywheel overcomes the pause phenomenon caused by alternation of the forward rotation and the reverse rotation of drive, the columnar rotor is made to be stable in rotation speed, and power generation is stable.