The invention discloses an ultrasonic auxiliary precision forging method and device, and relates to the field of forging. The ultrasonic auxiliary precision forging method and device comprise an upperconcave die, a lower concave die, an upper punch head, a lower punch head, an upper ultrasonic vibration mechanism and a lower ultrasonic vibration mechanism;and an ultrasonic vibration device penetrates through a punch cushion sleeve and a through groove in the middle of a template and is fixedly connected to the punch heads, an variable amplitude rod transmits the amplified ultrasonic vibrationto the punch heads, and the punch heads transmits the vibration to a blank. According to the ultrasonic auxiliary precision forging method and device, the frequency, the amplitude, the vibration modeof the ultrasonic vibration and the shape and the size of the punch heads are changed to suit for precision forging of different products; the method and device have the advantages that the plastic deformation capability of the metal is greatly improved, the metal filling property is improved, the friction force between the blank and the die is reduced, the grain structure is refined, the roughness of the forming surface is reduced, the demolding capability of the forge piece is improved, the applicability is wide, the material utilization rate and the product percent of pass are improved.