City image is also the carrier and external manifestation of city culture. Based on the theory of city image communication and social media data, this study constructs the categories of city cultural image and symbol carrier. Taking X city as an example, combining the statistical analysis method and the theme extraction model constructed by TF-IDF, TextRank and LDA algorithm, we analyze the characteristics of the cultural image and symbol dynamics of X city, and further analyze the audience’s emotional tendency. The overall city cultural image of X city is positive, with the content of humanistic image and social image as the main content, and the content of humanistic image is mainly the historical attractions and traditional culture, which account for about one percent of the total. The humanistic image is mainly about historical attractions and traditional culture, accounting for 48.3% and 40.8% respectively, and the social civilization style accounts for 91.4% of the content of the social image. The symbols of the city are mainly landscape scenery and food, but lack original music and technological facility symbols. 45.6% of the audience conveyed positive emotions towards the city’s cultural image, while 30.2% and 17.6% of the audience conveyed neutral and negative emotions. We should continue to dig deeper into the city’s cultural symbols, create high-quality content, and utilize social media platforms to promote the construction and dissemination of the city’s cultural image.