A quick port-switching method and associated apparatus are provided. A quick port-switching display control circuit includes a display controller, a first TMDS port, a second TMDS port and an analog video port. The display controller has a first GPIO pin and a second GPIO pin. The first TMDS port, second TMDS port and analog video port are coupled to the display controller for receiving a first TMDS input, a second TMDS input and an analog video signal, respectively. The first TMDS input and second TMDS input include a first hot-plugging signal and a second hot-plugging signal to be received by the first GPIO pin and second GPIO pin, respectively. The display controller determines whether the first TMDS input is valid by detecting whether the first hot-plugging signal is asserted, and determines whether the second TMDS input is valid by detecting whether the second hot-plugging signal is asserted.