The invention discloses a composite dressing device. The composite dressing device comprises a machine base, a cup-shaped grinding wheel and a spindle. The spindle is rotatably assembled on the machine base around the axis extending in the vertical direction. The composite dressing device further comprises an ultrasonic vibration system which is used for driving abrasive particles in the cup-shaped grinding wheel to vibrate at a high frequency. The ultrasonic vibration system is connected with the cup-shaped grinding wheel, so that longitudinal and radial coupled vibration, mainly radial vibration, of the cup-shaped grinding wheel is generated; by the adoption of the vibration form, the impacting and grinding effect of the abrasive particles is improved, and the area of the cup-shaped grinding wheel and the area of the grinding wheel to be dressed are increased. Under the action of the ultrasonic vibration, the impacting and grinding force of the abrasive particles to the grinding wheel to be dressed is improved, and the grinding progress is accelerated; the dressing efficiency of the grinding wheel to be dressed is improved in the way of combining ultrasonic dressing with cup-shaped grinding wheel dressing, and the problems that in the prior art, the dressing efficiency of a superhard grinding wheel is low, and the loss of a dressing tool is large are solved.