The invention relates to a method for identifying the warping of a compact disc. The method comprises the following steps of: controlling an object lens to move from a first extreme position to a second extreme position and emit light beams to a compact disc; detecting the light beams reflected by the compact disc and generating first focus error signals; calculating the number of first S curves formed by the first focus error signals; identifying a type of the compact disc; selecting a corresponding first preset number according to the type of the compact disc; judging whether the number of the first S curves is larger than the first preset number or not; and judging that the compact disc is warped if the number of the first S curves is larger than the first preset number. In addition, the invention further provides a device for identifying the warping of the compact disc.