A temperature compensation method for laser power in an optical disk drive is provided. A predetermined linear-fitting power curve and a temperature-changing slope curve are previously stored in the optical disk drive. Firstly, an output of laser power is controlled according to the predetermined linear-fitting power curve to read/write data. Next, the temperature of the disk drive is detected. Then, whether the temperature has changed is checked. If the temperature has not changed, the method continues to read/write data. If the temperature has changed, the method obtains a relative slope from the slope curve by use of the temperature of the disk drive, displaces the slope of the predetermined linear-fitting power curve with the obtained relative slope to form a new linear-fitting power curve for replacing the predetermined linear-fitting power curve, and controls the output of laser power.