A universal serial bus type-C interface circuit and a pin bypass method thereof are provided. The interface circuit includes a first configuration channel pin, a second configuration channel pin, a port manager and a port controller. The port manager has a first signal terminal and a second signal terminal. The port controller includes a multiplexer circuit and a control logic circuit. The multiplexer circuit is coupled to the first configuration channel pin, the second configuration channel pin, the first signal terminal and the second signal terminal. The control logic circuit is coupled to the multiplexer circuit and provides a multiplexer control signal to the multiplexer circuit in response to a switching request. The multiplexer circuit couples the first configuration channel pin and the second configuration channel pin to the first signal terminal and the second signal terminal respectively according to the multiplexer control signal.