A method and a system for automatically adjusting intensity of a signal outputted by an HDMI transmitter are provided. With the method, a length of an HDMI transmission line between the HDMI transmitter and an HDMI receiver is determined. A swing amplitude and a pre-emphasis intensity of the signal outputted by the HDMI transmitter are determined based on the length of the HDMI transmission line and a frequency of the signal outputted by the HDMI transmitter. An HDMI output drive circuit is configured based on the swing amplitude and the pre-emphasis intensity.