Statement of the problem. The article gives an explanation of the text generation and interpretation according to the Rhetorical structure theory (RST), developed by W. Mann and S. Thompson. This theory is based on structural and functional approaches in linguistics, which present the relations between the form and the content of a language unit as the structure of dependencies. The dependency of one language unit on another in the newly formed unity is understood as a function performed by the language unit in speech or discourse. RST provides as a model for analyzing semantic relations between nucleus (main) and satellite (dependent) discursive units that form the coherence of the text. Results. Different approaches to defining discourse and its structural components are described. The nucleus-satellite model of the discourse structure proposed by W. Mann and S. Thompson is analyzed. The authors of RST emphasize that the coherence of the text is based on rhetorical relations that connect the units of discourse and contribute to the adequate coding and decoding of information. The nucleus-satellite organization of discursive units distributes the addressee`s focus of text perception. The principles of graphic representation of rhetorical relations are revealed, as well as the principles of classification of asymmetrical and symmetrical, mononucleus and multinucleus rhetorical relations. Conclusion. Nuclearity and hierarchy are recognized as the leading ways of discourse structural organization in RST. Hierarchy can be traced not only in the semantic and intentional allocation of the nucleus, but also in the structural organization of rhetorical relations among discursive units. Thus, a nucleus-satellite model of discourse serves as an effective functional principle to generate and interpret texts, which used to solve various communication tasks.