Communication and interaction in bus transportation surely are needed by the driver, the driver assistant, and also the passengers. Speech act is an utterance that can consider an act. The codes or words used by the driver assistant is interesting to be analyzed by using speech act thoery. In this research, the writer tries to describe the codes or words and analyze the kind of speech act used in bus transportation of Semarang-Salatiga. The research uses a descriptive qualitative method which is done by describing and analyzing those objects. From the research, the researcher found that from those codes or words includes into word formation, word classes, and phrase. They also includes into locution, illocution, and perlocution, literal and non literal, and also direct speech acts. In conclusion, studying and understanding speech acts is important because it can make people be clearer to understand what other people exactly they are talking about in their daily life, and it also can be useful as a medium of linguistics science in education.