The present disclosure describes a data transmission method, a timing controller, a source driver, and a data transmission system. The method includes: when the timing controller transmits data to the source driver at a speed n times a preset speed, the timing controller suspends transmission of valid data with the source driver after completing transmission of a first data packet; and the transmission of valid data with the source driver is resumed at a transmitting time of a second data packet; the first data packet and the second data packet each includes valid data of a row of sub-pixels, or each includes valid data of a frame. The present disclosure completes the transmission of the first data packet in advance by increasing the transmission speed, then suspends the data transmission, and resumes the data transmission at the transmitting time of the second data packet, thereby reducing the power consumption.