Abstract: Research on humorous utterances focuses on the analysis of humorous utterances per se. This paper presents a first step to
assess the impoliteness and humor in a discourse on the basis of Brown and Levinson's politeness theory and Raskin's Semantic Script
Theory of Humor （SSTH） so as to ascertain that the dual quality （being impolite and humorous simultaneously） of social
communicative utterances can be determined. In this article the attempt is made to analyze the text informativeness from the
macroscopic（linear opposition of text script）and microscopic（linear increment of informativeness）perspective. Through the text
informativeness analysis, it is proved that the similarity features of the two scripts in the text are the most different in number, which
leads to the semantic opposition between the two scripts, thus achieving the humorous pragmatic effect of the text. This paper is
intended to set up an observable and verifiable testing method of semantic script opposition of impolite humorous utterances, which
develops the explanatory power of（im）politeness theory and SSTH.

Key words: impolite humorous utterances, text informativeness analysis, pragmatic effect, Semantic Script Theory of Humor