In response to the Communist Party of China’s call to “March Toward Modern Science, ” the All-China Association for the Dissemination of Scientific and Technical Knowledge and the All-China Federation of Trade Unions jointly convened the National Conference of Activist Workers in Science and Technology Popularization in Beijing in late October 1956. The aim was to foster closer collaboration between scientists and industrial workers while expanding the reach of science popularization. The conference, distinguished by its high-level organization, prolonged preparatory phase, and extensive participation, effectively galvanized workers’ enthusiasm for science popularization by recruiting activist employees into working groups and engaging them in the nationwide conference. During the preparatory phase, grassroots research helped formulate a guiding principle for science popularization—“integration with production, alignment with practical needs, and pursuit of broad outreach”—along with a methodology emphasizing “small-scale, diverse, easily understandable, and voluntary participation.” This landmark conference in the history of New China’s science popularization established the historical experience of mobilizing active participants to “strive for extensive reach” in science popularization, which continues to offer valuable insights for enhancing national science popularization capacity building in the new era.