Compared with semantic presupposition, pragmatic presupposition is a dynamic and complex linguistic phenomenon, and it plays a significant role in the weaving of a literary text. This paper, through analyzing the novel Native Son, examines the discourse functions in terms of economy, coherence and dramatic effect in the literary text from the perspective of pragmatic presupposition. In addition, the present paper hopes to open up new dimensions in the research, and help readers deepen their appreciation of the fictional text.