A method for controlling laser power of an optical disk drive is provided. Firstly, a power-controlling curve of a first loop circuit is formed according to a real test. Next, two test points are selected from the power-controlling curve. Then, the voltage outputted from a second loop circuit is adjusted. After that, whether the generated internal power signal is equal to the internal power signal of the two test points is checked. Afterwards, the voltage outputted from the second loop circuit is recorded. Then, the gain of the two loop circuits under the same change of the internal power signal is calculated. Lastly, a gained power-controlling curve of the first loop circuit is used as a power-controlling curve of the second loop circuit, such that the power-controlling curve is quickly obtained.