The article analyzes the concept of the educational environment, its components and features of the structure. The concept of educational environment design was introduced. The components of educational environment design for the teachers’ professional training of the Ternopil Volodymyr Hnatiuk National Pedagogical University (TNPU) are described: technological, didactic and social. Its characteristic features such as: information saturation and openness, digital transformation, social practices and cooperation are considered. The study of the effectiveness of the created design of the university's educational environment for teachers' professional development was conducted on the basis of TNPU. In total, 432 masters of all specialties of the University participated in this study. The study used the method of expert assessments for statistical processing of results. The study was conducted to determine the level of importance of all indicators of each component of the educational environment design. The results of the study illustrate the significant changes in the technological and social components of the university's educational environment design, which have a significant impact on the teachers’ professional training.