A portable electronic apparatus and a connection method therefore are disclosed. The portable electronic apparatus comprises a connector, a processing circuit, and a switch module. After a plug is plugged into the connector, the processing circuit reads a voltage value of the plug via the switch module. When determining that the voltage value of the plug is within a first voltage range, the processing circuit outputs switch signals to the switch module, so that an input signal of the plug is able to be transmitted to the processing circuit via the connector and the switch module. When determining that the voltage value of the plug is within a second voltage range, the processing circuit outputs other switch signals to the switch module, so that an output signal of the processing circuit is able to be transmitted to the plug via the switch module and the connector.