The invention discloses a plastic bottle sorting method. A sorting device is used in the method and comprises a first conveyor belt. A detection mechanism is arranged above the first conveyor belt. The detection mechanism comprises a white intense light source and a black absorption block. A positive temperature coefficient thermistor is arranged on the black absorption block. A receiving mechanism is arranged below the output end of the first conveyor belt. The receiving mechanism comprises a rack, a mounting seat and a connecting plate. The middle portion of the connecting plate is hinged to the mounting seat. A second conveyor belt is arranged on the left side of the mounting seat. A third conveyor belt is arranged on the right side of the mounting seat. An electromagnetic block is arranged on the rack. A magnet exciting coil is arranged on the electromagnetic block and electrically connected with the positive temperature coefficient thermistor. A second switch and a third switch are arranged on the rack. A second vertical rod and a third vertical rod are arranged on the connecting plate. By the adoption of the scheme, manual intervention is not needed during sorting of plastic bottles, and the problem of the high cost caused by manual sorting is fully solved.