Different from the art of persuasion in Western classical rhetoric, Roland Barthes' concept of visual rhetoric pays more attention to the implicit meaning of image information, and has become an important tool and carrier for documentaries to convey messages with rich connotations, explanations and performances. Having reviewed previous literatures on visual rhetoric, this paper looks at the issue from a new angle, beginning with the three dimensions of language, image and comprehensive elements of visual rhetoric research. Based on the visual images of the new media documentary "The Human World . Special Program Against Epidemic Situation" which was released on May 21, 2020, this paper analyzes path and construction mode of rhetorical meaning of the documentary.