A driving device includes a motor, a first rotating portion, a second rotating portion, a piezoelectric assembly, and a controlling unit. The motor includes a rotating shaft. The first rotating portion is fixed to the rotating shaft. The second rotating portion is engaged with the first rotating portion. The piezoelectric assembly is sandwiched between the first rotating portion and the second rotating portion. The controlling unit is electrically connected to the motor and the piezoelectric assembly. The controlling unit is configured for storing a predetermined voltage, and determining whether an electric voltage output by the piezoelectric assembly is greater than or equal to the predetermined voltage and inactivating the motor if the electric voltage output by the piezoelectric assembly is greater than or equal to the predetermined voltage. A protection method for the driving device is also provided.