A timing control circuit and an operation method thereof are provided. The timing control circuit includes a receiving circuit, a line memory, and a timing generating circuit. The receiving circuit receives a video packet stream from the outside and provides an external horizontal sync signal and a first data signal. The line memory temporarily stores the first data signal, and outputs a second data signal to a source driver according to an internal horizontal sync signal generated by the timing generating circuit. A video frame period of the second data signal includes a video display operation period and a touch detection period. A video display operation period is divided into a plurality of sub-periods. The timing generating circuit performs a synchronization operation in each of the sub-periods, so as to synchronize the timing of the internal horizontal sync signal with the timing of the external horizontal sync signal.