Provided is a method and an apparatus for controlling a write parameter according to a voltage variation. The method for controlling the write parameter includes monitoring a voltage supplied to a pre-amplifier before performing a write operation and adjusting the write parameter supplied to the pre-amplifier based on the monitoring result. Controlling the write parameter includes reading a predetermined write parameter from a write parameter table based on the monitoring result, and adjusting the read write parameter to the write parameter which will be supplied to the pre-amplifier.