Generative artificial intelligence, as an important transformative force in contemporary communication technology, is profoundly changing the generation mechanism of communication content and the implementation path of communication effects. From a semiotic perspective, this article explores how AI technology can reconstruct the symbolic construction logic, content form, and discourse power structure in communication content, and further analyzes its impact on audience perception, information reception, and feedback mechanisms, communication controllability, and uncertainty at the level of communication effectiveness. Research has found that the deep intervention of AI has led to structured, programmatic, and mimetic dissemination of content. The decoding path of the audience is becoming increasingly complex, and the feedback is more immediate but lacks depth. At the same time, it also brings potential risks such as unclear ethical responsibilities and decreased information authenticity. At the end of the article, a thinking path for future communication research and practice is proposed from four dimensions: ethical regulation, platform responsibility, human-machine collaboration, and disciplinary integration, aiming to provide a theoretical reference for building a more rational, standardized, and human-oriented AI communication environment.