An overview of modern approaches to the concept of "decentralization of power" is given in the article. The essence of decentralization as a political and legal reform has been systematized. The decentralization specific influence on the stimulation of economic development of territorial communities’ business environment is investigated. It is defined that one of the main peculiarities of decentralization of state power in Ukraine is that at the same time the processes of local self-government reform, territorial organization of executive power, administrative-territorial organization and state regional policy are ongoing. The dynamics of united territorial communities creation in Ukraine in 2015-2019 is researched. It was found that Zhytomyr, Chernihiv, Khmelnytsky, Zaporizhia and Dnipropetrovsk regions showed the best results in the general rating of regions in terms of the number of united territorial communities to be established. The financial aspects of the united territorial communities activities in Ternopil region are analyzed by the analytical indicators grouped in the following four groups: income per capita; level of budget subsidies; share of administrative expenditures in the community budget; share of wages in the general fund expenditures. Based on the conducted analysis, positive changes in the community budget and state support are identified, which helped to develop a favorable climate for business development in the region. Ukraine's position in the Doing Business rating in 2019 has been analyzed. The research results show that it has significantly improved its position, in particular, due to decentralization. Prospects for the development of territorial communities’ business environment under conditions of decentralization reform are outlined based on the conducted analysis.