At the beginning of the outbreak of the COVID-19 pandemic in 2020, a public discussion about “whether scientists should first prevent and control the epidemic or publish papers” was triggered by academic publish in the New England Journal of Medicine. During this discussion, a science communication influencer, named “Bi Dao” adopted two media types (long article and video) successively but with the same series of scientific evidence to persuade the public to accept his statement “the laboratory is also the battlefield to save lives”, and he used two different platforms to do the persuasion, the WeChat and the Bilibili, respectively. Based on the above background, two experiments were conducted and framed by the Elaboration Likelihood Model (ELM). The peripheral route, in here, was operationalized as “professional identity of the source” and manipulated, and the interplay between eHealth literacy and media type were studied. The results of the two experiments showed that the text format was more persuasive for audiences with higher eHealth literacy, while the video format had no significant effect on the relationship between eHealth literacy and intentions to accept information; the professional identities of online science opinion leaders had no significant effect on the relationship between eHealth literacy and intention to accept information, which contradicted the traditional ELM hypothesis of the influence of sources as heuristic cue. The paper also discussed the limitations, theoretical and practical applications of the research, especially under the context of the pandemic and social mediated science communication.