Financial planning of state-owned enterprises as a management function ensures the formation, use, structuring and evaluation of resources for a year. To ensure the achievement of sustainable economic development of state enterprises, the substantiation of the concept of planning economic activity, the development of methodological and organizational approaches to the process of drafting financial plans is relevant. The purpose of the article is to substantiate the theoretical and practical principles of organization of planning economic activity as an element of economic policy at state-owned enterprises in the system of strategic management. Taking into account the unprofitable activity of most state enterprises of Ukraine, the methodical principles of financial planning are updated due to the possibility of ensuring the functioning of the enterprise by the available resources (financial and material). The article describes the organization of financial planning of economic activity of state enterprises in Ukraine and the procedure and structure of its formation and presentation. It also highlights the use of the concept of strategic management, which eliminates the extrapolation of past events, but indicators of which are calculated on the basis of trends of the enterprise, market and industry development, patterns, risks, assumptions. The methodical aspects of planning under the conditions of non-profitability or profitability of enterprises are described, which is the basis for determining the potential of the enterprise in terms of segments (types of activities). It is proposed to implement procedures for amending the approved financial plans on the basis of good reasons for compelling reasons, which are briefly formulated. Economic conditions that are appropriate to take into account when considering and approving economic policy for the implementation of financial planning are recommended and their content is disclosed. Methodical techniques of financial planning of economic activity, using flexible planning, introducing a threshold for making changes to financial plans, foreseeing a new section in the explanatory note “Changes to the financial plan” are proposed.