Abstract: In the time with 5G technology, the "post-truth era" is forcing mainstream media to innovate news production models and discourse expression paradigms. The immersive journalism imposes strong effects on the mainstream media in such areas like building a mediated society, reconstructing communication channels, strengthening the network connection between people, information and emotions, promoting the media integration in the popularization pattern, deepening the competition and cooperation of market resources, and finally creating connections beyond the information dissemination. It also helps mainstream media re-control the propaganda and build a new social communication model. Although immersive journalism has brought opportunities for the development of mainstream media, the current production dilemma is still obvious: the mainstream media news production system has not been closed-loop and stable, and immersive journalism has become "chicken ribs". The authenticity of immersive journalism needs to be confirmed, and the issue of ethical anomie needs to be responded to urgently. The applicable scenarios of immersive journalism are not yet clear, which can easily lead to risks such as loss of value control. To this end, the mainstream media should firstly accelerate the closed-loop finalization of the news production system and stabilize the profit-realizing model. Secondly, they should adhere to the principle of truth and enhance their creative ability in the context of "strong interaction" with the audience. In the third, the precise control of reporting boundaries is needed so that the system masters the applicable scenarios of immersive journalism.