The invention discloses a punching device after bus pyrocondensation processing and a method of the punching device after bus pyrocondensation processing and relates to a punching device. A square inverted-cone-shaped block (4) and a square cone-shaped block (9) are respectively corresponding surfaces of the inner sides of two ends of a U-shaped plate (6). A screw (2) penetrates through the outer side of the U-shaped plate (6). A light hole (3) of the square inverted-cone-shaped block (4) is connected with a screw hole (10) of the square cone-shaped block (9). The punching method includes: finding a punching position, punching, manufacturing square holes and processing inside the holes. The punching device after the bus pyrocondensation processing and the method of the punching device after the bus pyrocondensation processing are capable of enabling the square inverted-cone-shaped block and the square cone-shaped block to extrude heat shrink tubes at the upper end and the lower end of the bus square holes and are standard in the manufactured square holes.