A method for inspecting LED dies includes the following steps. First electrodes and second electrodes of LED dies to be inspected are short-circuited via a conductive layer on an inspection substrate, or an inspection bias voltage is applied between the first electrodes and the second electrodes of the LED dies. An excitation light is irradiated on the LED dies to be inspected on the inspection substrate such that the LED dies to be inspected emit a secondary light. When the first electrodes and the second electrodes of the LED dies to be inspected are open, short-circuited, and/or subjected to the inspection bias voltage, the secondary light is captured via an optical sensor. An output of the optical sensor is received via a computer and a spectrum difference of the secondary light is calculated to determine whether the LED dies are abnormal or to classify the LED dies to be inspected.