There are many science-fiction writers in English literature and Vonnegut is a quiet interesting writer with lot of scientific thoughts but he strongly denies to be called as a Science fiction writer. In his writings strong anti-war sentiments are expressed and conveys anti-war beliefs. Strangely enough, Slaughterhouse-Five along with much of his other writings are strongly non-sentimental in order to convey these anti-war beliefs. While sentimentality and emotional appeal are typical approaches to rhetorical arguments, Vonnegut often disregards sentiment in favor of reductive reasoning in favor of a moral point he is trying to make. This paper explores at showing Vonnegut has Humanistic approach in his writing.