Charles W. Morris (1901-1979) is one of the important representatives of American pragmatism in the mid-20th century. He inherited and developed Peirce’s semiotic theory and Mead’s social behaviorism, and, on the basis of combining them, he advanced his own semiotic theory—behavioristic semiotics, which has exerted a significant influence on the later semiotic studies. Language, as a complex sign system, belongs to the category of semiotic research. Meanwhile, translation is closely related to language, involving the application, interpretation and conversion of different signs, and there are many problems in the process of advertising translation, such as inappropriate choice of words, confusion of word order, etc. So in this paper we shall conduct the advertising translation research on the basis of semiotics from the following aspects: the application of syntactics, semantics, pragmatics and the unity relations among them, to analyze how to make proper transformation between different languages, thus, readers can get a better understanding of the fact that advertising information is conveyed through the combination of signs, and a good application of behavioristic semiotics in advertising translation would give full play to the functions of advertisements in sales promotion. This paper is based on Morris’s behavioristic semiotics, and adopts the methods of literature retrieval and a combination of theory and examples, mainly studying the application of syntactics, semantics, pragmatics and the unity relations among them in advertising translation. The research findings on the application of behavioristic semiotic theory in advertising translation are summarized as follows: (1) at the syntactic level, when dealing with the advertising translation, we should take into consideration the phonetics, numbers, gender and word order, thus avoiding the confusion of language and achieving a better and more accurate translation; (2) at the semantic level, in order to highlight the outstanding characteristics of products, we should think about the usage of signs from word level, sentence level and text level, thus the advertising translation can make the characteristics of products more attractive; (3) at the pragmatic level, analysis of the speech act theory, conversational implicature and context can reduce the frequency of pragmatic failure,; (4) the unity relations among these three aspects also exert a significant influence on advertising translation, that is, to make the advertising translation more appropriate. According to our study, the application of the semiotic theory can make the advertising translation better, reflect the original intention of ads more effectively, meet the consumers’ needs better and finally realize the best promotion of ads.