A method and an apparatus which controls write power of an optical driver by optimizing the number of channels used to drive a laser diode in a write mode while stabilizing the level of a write power voltage at an early stage of the write mode. The method of controlling the write power includes checking whether the write power provided to the laser diode included in the optical driver is stable, controlling the write power by increasing the number of channels used to control the write power so as to provide sufficient write power to drive the laser diode in response to the write power provided to the laser diode being unstable, and controlling the write power by using less channels than the channels used in response to the write power being unstable in response to the write power provided to the laser diode being stable. Accordingly, it is possible to reduce the size of a firmware by preventing channels unnecessary to perform a write mode from being used.