The invention provides an edge-tearing and opening device and an edge-tearing operation method. The edge-tearing and opening device comprises a fixing base (5), a rotary shaft (7), tool rests (8) and blades (10). A movable connecting structure is formed between the rotary shaft (7) and the fixing base (5); the rotary shaft (7) rotates relative to the fixing base (5); one ends of the tool rests (8) are fixedly connected with the rotary shaft (7); the other ends of the tool rests (8) form blade installation seats (81) with U-shaped structures; and the blades (10) are fixedly connected onto the blade installation seats (81). When the edge-tearing and opening device is utilized for carrying out edge-tearing operation, two opposite and parallel cutting edges can be easily processed, and the cutting edge positioning accuracy is high, so that the processing quality of the cutting edges is ensured, and the operation efficiency of the cutting edges is improved; and the cutting edges are utilized as tearing guided openings, so that the edge-tearing operation can be easily and quickly completed, the edge-tearing operation quality and the operation efficiency are effectively improved, and the labor intensity of operating personnel is effectively reduced.