A method for determining a disk type is provided. In the invention, a pickup head of a DVD optical drive is moved to a blank area of the disk where no data is stored. After rotation of the disk is stopped, the blank area is irradiated with a laser beam, and reflective signals reflected from a surface layer and a reflective layer of the disk are measured respectively. According to a time difference between the two reflective signals, the type of the disk placed in the DVD optical drive is determined. Therefore misjudgment because of effects of pits in a data area of the disk on the reflective signals can be avoided, so that the disk type can be accurately determined.