A low speed control method and an apparatus for a servo motor. The control apparatus comprises: an encoder capable of acquiring a speed signal from a servo motor and encoding the speed signal to output a low-resolution encoded signal; an insertion calculation unit capable of receiving the low-resolution encoded signal from the encoder to be processed by an interpolation operation for converting the low-resolution encoded signal into a high-resolution encoded signal to be outputted therefrom; a servo control chip capable of setting internal parameters and receiving the high-resolution encoded signal from the insertion calculation unit to be processed by a calculation process so as to output a switch control instruction; and a power module capable of receiving the switch control instruction from the servo control chip and then transmitting the same to the servo motor for adjusting the operation speed of the servo motor.