National rhetoric is essentially a practice of constitutive rhetoric and is closely related to its core assumptions and areas of study. The construction of national rhetorical competence in the field of science and technology communication is an important part of national rhetoric, which directly determines the international communication effect of China’s science and technology development and the construction of national image. Starting from the perspective of constitutive rhetoric theory, this article analyzes three aspects related to the construction of national rhetorical competence in science and technology communication, including national rhetoric awareness, goals and strategies, and focuses on discussing the ways to implement national rhetorical strategies from three aspects: the value identification strategy of constructing a rhetorical ecology integrating science and technology and culture, the opposition identification strategy of challenging the “Western-centrism” discourse pattern, and the style identification strategy of creating a constructive journalism style with Chinese characteristics. In the current situation of global science and technology competition, the theoretical and practical research on national rhetorical competence in the field of science and technology communication will be further emphasized.