The invention discloses a medical disposable electric motor saw, which comprises a handle and an enclosure main body, wherein a non-removable battery and a circuit control panel which is connected with the battery are arranged in the handle; a press part of the handle is provided with a speed adjusting switch which is connected with the circuit control panel; a hollow motor which is provided with a driving shaft is arranged in the enclosure main body; the battery is a rechargeable lithium battery; a charging socket is formed in the bottom or the lateral part of the handle; a sterile sealing bag is arranged on the outer sides of the handle and the enclosure main body. After the structure is adopted, and the hollow motor is used, the medical disposable electric motor saw is stable in transmission and good in braking performance, the weight of the medical disposable electric motor saw is about a half of that of an electric motor saw with a common motor, the structure is simple, the fault rate is low, the medical disposable electric motor saw is easy to carry and use, the manufacturing cost is low, the battery cannot be detached, so the loosening or dropping phenomenon cannot occur, and the completion quality of a surgery is effectively ensured. The sterile sealing bag is used, the wait for high-temperature high-pressure sterilization is not needed, and the medical disposable electric motor saw can be used any time. The precious operation time is saved for an emergency operation patient.