An optical disk writing and reading apparatus and a method thereof is provided. The optical disk writing and reading apparatus has an optical pick-up for writing or reading data on an optical disk by using a laser light of a certain wavelength, an optical power calculation part for calculating an optical power of the laser light generated from the optical pick-up, and a micom operating the optical power calculation part by every certain time to detect the optical power of the laser light and adjusting the optical power of the laser light based on a preset optimum optical power to be optimized while writing the data on the optical disk.