PET Bottle Piercer is to perforate PET bottle with the rotating knives. The holding and the cutting knives from special steel cut the PET bottles of different sizes efficiently. The speed of the two rotors are different for the high efficiency. The knives are replaceable to save the maintenance cost. The big diameter shafts minimize clogging and jamming problems, and it is easy for the operators to do the maintenance through the two hatches located on both sides of the machine. The safety sensors will stop the machine for the hatch opening.