The invention discloses a special-shaped label cutting mechanism for a labeling machine. The special-shaped label cutting mechanism comprises a frame body, a label feeding mechanism and a label collecting mechanism. A label cutting mechanism is arranged between the label feeding mechanism and the label collecting mechanism. The label cutting mechanism comprises an upper die and a lower die. The upper die comprises a punch. The upper die is connected with a first driving device. An ultrasonic welding head and a second driving device are arranged below the lower die. The lower die comprises a lower die body. A die hole matched with the punch and a welding hole for containing the ultrasonic welding head are correspondingly formed in the upper end and the lower end of the lower die body. Through yarn holes are formed in the front end and the rear end of the lower die body. Through label holes are correspondingly formed in the left end and the right end of the lower die body. The die hole communicates with the welding hole. A yarn groove is formed in the bottom face of each yarn hole. The label holes are located above the yarn holes. By the adoption of the special-shaped label cutting mechanism, cutting of special-shaped labels and connection of yarns are completed together through the label cutting mechanism, and the problems that cutting and integrated cutting of the labels cannotbe achieved, and the purpose that the labels and the yarns are connected with special-shaped labels cannot be achieved by means of the prior art are solved.