With the advent of Ukraine’s independence, its border guard policy was aimed at ensuring territorial integrity, establishing its own border security system, organizing border protection around the perimeter and protecting the exclusive (marine) economic zone. Protection of the state border of Ukraine is an integral part of the national system of protection of the state border and is performed by the State Border Guard Service of Ukraine on land, sea, rivers, lakes and other reservoirs, according to the powers granted to ensure the integrity of the state border of Ukraine. The article is devoted to the research of the formation of the state border protection system as a mechanism for ensuring the integrity of the state border of Ukraine. The author analyzes the stages of formation, problems and prospects of the protection of the state border of Ukraine through the prism of the activity of the border guard authority of Ukraine on the implementation of the border gurd policy. Based on the analysis of adoption and implementation of legal acts, concepts and programs of strategic importance in the field of protection of the state border (a feature of planning), as well as taking into account the scientific achievements of scientists and variability of the security environment that led to changes (a sign of development), the process of formation and development of the state border protection system is proposed to be divided into five periods, namely: the first – 1991-1993 (on the basis of planning and development);the second – 1994- 1999 (on the basis of planning and development);the third – 2000-2005 (on the basis of planning), 2000 – July 2003 (on the basis of development);the fourth – 2006-2015 (on the basis of planning), August 2003-2013 (on the basis of development);the fifth – 2016-2020 (on the basis of planning), 2014 - 2020 (on the basis of development).The results of the retrospective analysis allowed to establish the following patterns of formation and development of the state border protection system:1. The border guard policy is aimed at ensuring territorial integrity, establishing its own state border protection system and protection of the exclusive (marine) economic zone. 2. Formation of the state border protection system is influenced by a number of factors, including: the peculiarity of the geographical position of Ukraine (presence of international transport corridors; presence of «frozen» conflicts in the regions bordering on Ukraine; unregulated migration and smuggling activities; the need for significant resources for the border infrastructure development, etc.). 3. The functional complexity of the border guard institution evolves in the direction of: militaristic – law enforcement – law enforcement and militaristic.4. The increasing level of integration of subjects, which provide border security in the security space. 5. Increased attention to the need for balancing vital interests in the field of state border protection. 6. A noticeable tendency to increase the capacity of the state border guard system to counter current threats: armed conflicts at the state border, smuggling of weapons, drug trafficking, unregulated migration, illegal extraction and theft of national treasures, etc. 7. Determining of strategic directions of ensuring the border security is carried out at the highest state level within the framework of the Comprehensive Review of the Security and Defense Sector, drafting of the Conceptual Basis for the Reform of the Law Enforcement Agencies and the Concept of the Reform of the Criminal Justice of Ukraine. 8. When elaborating approaches to the development of the state border guard system (close, medium and long-term perspective), it is necessary to take into account the experience of the new EU member states in preparing for accession to the EU and joining the Schengen agreement.