An optical disc apparatus and a method of performing an optical power study and detecting writing power in the optical disc apparatus. An optical pickup includes a light source to emit a laser beam according to an input optical power signal, an optical power detector to detect optical power of the laser beam using part of the laser beam, and an actuator to drive a lens to form a beam spot. To reduce the time required for the power study, a controller positions the optical pickup in a specific area of a disc and applies a predetermined range of optical power signals to the light source to perform the power study to determine its optical power characteristics using the optical power signal and the detected optical power while maintaining the actuator in a driving state in which writing and reading is possible.