Abstract: A protective case is configured to receive and protect an electronic device with an audio interface. The protective case includes an audio jack aligning with the audio interface of the electronic device, an earphone connected to an earphone wire, a circuit board, a plurality of contacts set in the audio jack and connected to the earphone wire via the circuit board, and an audio connector. The audio connector includes a base and a connection-peg. The base includes a plurality of metal contacts, and each metal contact corresponds to one contact. The connection-peg is electrically connected to the plurality of metal contacts. When the connection-peg is inserted into the audio interface of the electronic device via the audio jack, the plurality of the contacts are correspondingly and electrically connected to the plurality of the metal contacts, and the electronic device is electrically connected to the earphone.