The notions of activity, activization and subject of activity are analysed. The problem of activization of schoolchildren's professional self-determination is the problem of their upbringing as the subjects of congnitive, educational, working activity and personal contact. The basical characteristics of subject of activity are stated, ^and subject activity forms are described. Using general notion of subject of activity the notion of personal professional self-determination is worked out, the structure of situation of professional self-determination is given. Complex program of active professional orientation for schoolchildren using the principles of active social-psychological influence is proposed. The system of dynamics' diagnostics of schoolchildren's active professional self-determination is described.