While we live in an era where documentaries are produced in a shifting landscape of a weak industrial environment, why are directors still eager for driving changes in society by making documentaries? If stories inspire sympathy, why do we need to measure the social impact of documentaries? In addition to the evolving technologies, emerging digital business models, transforming consumer behavior, and uncertainty about aesthetic value framework, what potential value and impact are there to be discovered? From the perspective of documentary aesthetics and ethical framework to interpret social impact, or simply to measure documentary with economic value, it is no longer able to meet the needs of a contemporary dialectical discourse of cultural value interactive with economic, social and public value logic of documentary. It is critical for the documentary community to take an active role in establishing more equitable value discourse systems. The fundamental question is how to shape the cultural value of documentaries, no matter whether the purpose is to rewrite the history of Taiwanese documentaries, or to create a cycle of cultural and economic value, building a discussion mechanism of value and impact discourse is the only way to expand the research spectrum of documentary study limited to production, aesthetics, and political history. This article takes the impact and value approach of discussing the cultural value and social impact intertwined with each other in documentaries. It constructs a dialectical discourse mechanism for the discussion of documentary cultural value, public value and social value beyond the documentary industry perspective. As for the future study, by sorting out the cultural value context of Taiwanese documentaries, it is urgently tasked to establish stronger, more sustainable infrastructures that better support the diverse ecosystem values of documentaries.