It is developed the model of high school seniors’ professional competence increasing through communicative action, which is built of three interrelated components: awareness of professional plans, finding ownself in the chosen profession, self-actualization in professional choice. The experiment idea was to open to high school seniors the possibility of applying their internal needs of professional self-realization in their already chosen profession. The aim was to study the role of communicative action as a means for professional self-awareness development in high school seniors. To assess the dynamics of the communicative attitude of high school students, we analyzed the results of V. Boyko’s «Communicative attitude» testing by the mathematical t-Student method before and after the experimental intervention. The experimental group results showed the improvement, that is the decrease in the negative communicative attitude. There were also revealed statistically significant differences in indicators of communicative attitude with different types of professional self-determination of high school students. It is proved that the willingness to respond in a certain way to interpersonal interaction is determined by the factor of communication experience, namely, assessments and experiences of the essence of the acquired experience, views, and behavior. These indicators differ significantly depending on the professional self-determination of high school students. It is concluded that the increase of professional competence through communication leads to the improvement of mental and emotional state, and creates a new internal situation for professional self-determination optimization. The condition of professional self-determination, which can be used by a psychologist in career guidance work, is the use of informational action to start rethinking high school seniors’ own reality, which accordingly forms the strategy of their behavior. The further research perspective is seen in the development of professional psychological training and the use of the method of causometry in high school students.