A display and an operating method thereof are provided. The display includes a display panel, a timing controller, and a plurality of source drivers. The timing controller has a plurality of signal output terminals. The source drivers are coupled to the timing controller and the display panel. The timing controller outputs a plurality of training packets to the source drivers. When the source drivers lock a clock of the timing controller according to the training packets, the timing controller outputs a plurality of control packets and a plurality of color data packets to the source drivers. The source drivers respectively output a plurality of pixel voltages corresponding to the color data packets to the display panel according to the corresponding control packets. The training packets, the control packets, and the color data packets are serially transmitted to the source drivers via the signal output terminals.