The present invention discloses a portable device and a method of controlling HDMI signal output therein. The portable device comprises: a microcontroller unit, a USB Type-C interface, and a plurality of analog switches. Each of the analog switches is arranged between a HDMI signal output pin of the microcontroller unit and a corresponding pin of the USB Type-C interface. The microcontroller unit is configured to detect a positive or reverse insertion direction of the USB Type-C interface, and output a corresponding control signal to the analog switch according to the difference of the insertion direction. The analog switch is configured to shift a switching direction according to the control signal so that the HDMI signal is output through a corresponding pin of the USB Type-C interface.