Cannes Lions International Festival of Creativity is not only an important ceremony of advertising rewards, but also a platform of all attenders and a signal of the global advertising industry. The forum topics in 2015 show diversity of participant regions and advertising subjects in the industry. Media evolution and social function of ads both become essential topics this year. This article makes a content analysis on totally 486 forums from 2013, 2014 and 2015 Cannes Lions International Festival of Creativity in order to find out the thematic evolution of the forums. Besides, the discussion on thematic evolution will be taken from organization and structural perspective, technology and consumption environment, as well as industry practice.