The embodiment of the invention discloses an audio and video propagandizing method and system based on a robot. The method includes the steps that audio and a video are played through a first display screen, and the emotional characteristics of persons in the audio and the video are acquired; in a pre-established expression image library, at least one expression image corresponding to the emotional characteristics is determined; and the at least one expression image is displayed through a second display screen, wherein the robot is an inverted-Y-shaped robot, and the second display screen is located on the head area of the robot. By means of the scheme, the effect of accordingly displaying the corresponding expression is achieved while the robot plays the audio and the video, the using modes of the robot are extended, and the audio and video propagandizing vividness is also improved.