The paper considers peculiarities and tasks of psychological support for athletes’ preparation in the process of long-term athletic advancement. Specifics and differences in manifesting psychological functions at different stages of long-term preparation as an indicator of athletes’ mental state were studied. Psychological factors affecting the process of long-term advancement of athletes were analyzed taking account of the dynamics of rational and irrational mental functions. Psychological support objectives at each preparation stage were of defined. The objectives of psychological support actual at all stages of multi-year athlete's preparation were identified. Peculiarities of psychological support for athletes at the stage of withdrawal from elite sport were considered. The system of knowledge was developed to provide the psychological support for long-term preparation of athletes that includes the mental preparation, organizational and methodical aspects, psychological components of sports preparation efficiency provision and directions of psychological provision in the process of athletes’ selection and orientation of their preparation.