Based on the research framework of Pragma-Dialectics, this paper analyzes and evaluates the Foreign Ministry’ former spokesperson Liu Weimin’s reply to a question concerning the Sino- US tombarthite trade friction. Through this case study, we intend to develop a pragma-dialectical study approach to the spokesperson’ replies at the press conferences of China’s Foreign Ministry. It is comprised of three interrelated parts: reconstruction of argumentation, analysis of strategic maneuvering and critical evaluation. Our research disclosed that Liu exerts strategy maneuvering all through the four period of critical discussion in order to keep a balance between dialectical reasonableness and rhetorical effectiveness, Liu’s strategic maneuvering is reflected prominently in his proper manipulation of potential topic, audience demand and means of presentation in redefining the disagreement, selecting common points, designing the demonstration and reaching conclusion. Comparing with the regulation of critical discussion in pragama-dialectics, take the Sino-US tombarthite trade friction as background, we found that Liu Weimin’s manipulation on argumentative replies stills exists weakness. Our study makes it clear that the spokesperson still need to integrate both on dialectical and rhetorical perspectives.