Based on the background of the new media era, this paper takes the research on the online advertising marketing characteristics of LEGO “Rebuild the World” series as an example to explore how brands should play the advantages of online marketing under the new internet background, update the creative thinking of online marketing communication, and achieve the purpose of clarifying the target consumer group positioning and optimizing the brand image. By combining the Method of combining observation and content analysis, the author found 3 characteristics of Lego “Rebuild the World” series online advertising, which are: using LEGO bricks to connect the seemingly unconnected toy world with the real world, showing the richness, diversity and plasticity of LEGO bricks; cleverly designed with lots of elements to maximize the imagination of adults and children; closely connected the digital world with the real world, making the online advertising of LEGO “Rebuild the World” timely, progressive and universal. In addition, in view of the updating of online marketing modes of major brands in the era of new media, the author also puts forward corresponding thinking: how to improve the fit between the host broadcast with goods and the brand image, and how to rationally apply the Internet platform to realize the updating of online marketing modes.