A structure of light-emitting diode (LED) dies having an AC loop (a structure of AC LED dies), which is formed with at least one unit of AC LED micro-dies disposed on a chip. The unit of AC LED micro-dies comprises two LED micro-dies arranged in mutually reverse orientations and connected with each other in parallel, to which an AC power supply may be applied so that the LED unit may continuously emit light in response to a positive-half wave voltage and a negative-half wave voltage in the AC power supply. Since each AC LED micro-die is operated forwardly, the structure of AC LED dies also provides protection from electrical static charge (ESD) and may operate under a high voltage.