The paper discusses the method of text modeling of scientific and technical texts (based on the example of technical documentation to be written by students – the future IT specialists). Research methods are the critical review of the literature, the method of generalization, analogy and the method of structural and semiotic modeling. The main compositional speech forms typical for technical documentation texts are determined. The communicative purpose, macrostructure and linguo-stylistic peculiarities of scientific and technical texts are analyzed. The concept of text modeling, compositional speech forms are given in terms of teaching ESP writing. The paper outlines the main microelements that make up the text, text links, and model elements. The paper deals with the results of the study thus promoting deeper understanding of the communicative intentions and compositional structure of scientific and technical texts macroelements. The analysis of 70 technical documentation texts enables us to distinguish a typical sequence of compositional speech forms in the technical documentation texts (user guides to software development). There are the following compositional speech forms outlined in the introduction: definition, explanation, paraphrase and list; for the main part – explanation, message (informational), description; for the final part – description, reasoning (to justify actions), reasoning (for description and instructions). Using text modeling in teaching technical documentation writing allows students to be aware of: - communicative task of the text and its pragmatic purpose; - types of compositional speech forms and their sequence in the text; - structural components of specific compositional speech forms. The results of the study allow us to describe the communication units and deepen understanding of the internal classification of scientific and technical style. Methods of identification and analysis of structural varieties of compositional speech forms are used in the text modeling in the process of technical documentation writing. The main purpose of text modeling is to use the model to describe the features of the object. The text modeling consists of the main stages: 1) determine the genre of the text and its core component; 2) identify compositional speech forms that are typical for the genre; 3) describe the units of text composition.