Fundamental aspects of the issue of strategic stability of economy are studied in the article in terms of the system economic theory. Economic dynamics as a cyclic process including the alternating periods of pre-crisis, crisis, post-crisis and intercrisis development is offered for consideration. The structural model of interaction of key subsystems is made: economic science; social and economic policy; spheres of management of economy; economic behaviour («real economy»), taking into consideration the stage of internal life cycle of every subsystem and its influence on economy in general. Interaction of these subsystems is considered as an internal system resource of economy. The economy involvement as a national subsystem in interaction with such subsystems as society, government, business, is considered as an external system resource of economy. Mechanisms of restoration, achievement and preservation of economic stability due to management of the internal and external system resource and its effective use are revealed.