Abstract: Analyzing The Dead Father, a novel written by American Writer Donald Barthelme, from the perspective of the Postmodern Sublime aesthetics advocated by the French philosopher Jean-François Lyotard, the article points out that the text of the novel represents the aesthetic characteristics of the postmodern sublime in three aspects: indeterminacy, "the inhumain" and the unpresentable. Dead Father's being in the state of "differend", the inconsistence and discordance between lines in the text, and Dead Father's repudiated age with the negation of the linear time, are the representations of indeterminacy, which triggers the awareness of nihility that eventually directs at the postmodern sublime. "The inhumain" under the control of the scientific and technological ration leads to the waning of affect of human beings, while the readers' contemplation of "the inhumain" producing the sentiment of the postmodern sublimity, which extricates themselves from the technical and material control. The dissolution of the ubiquitous influence of Dead Father and his ability to arouse fear is the negative presentation of the unpresentable, therefore, through the negative presentation, the postmodern sublime is presented.