Introduction. The scale of pandemic and war in Ukraine was not fully forecasted, but the crisis phenomena of these disasters have specific signs. One of the priorities of the tax and budget policy is resilience to threats, both foreseeable and unforeseeable. Problem Statement. The full-scale Russian invasion of Ukraine has led to significant changes in the resource base, economic potential and the common system of public finances, these can no longer function on pre-war principles. New realities, both internal and external, have emerged; it is impossible to ensure the successful development of the state without scientific understanding of them. Purpose. Justification of directions for the formation of internal pillars of stability and security of the economic development of Ukraine through transformations in Public Financial Management (PFM) during the period of martial law and post-war reconstruction. Methods. Based on trends in statistical indicators, a comparative analysis of national anti-crisis reforms in the field of public finances was conducted. The methodology of the system approach, methods of factual, situational analysis and synthesis were used. Results. Ukraine's acquisition of the status of a candidate for the EU membership, the modern realities of statehood and national economy recovery amid when the signs of fundamental turmoil in the global economic space, require significant changes in the PFM. It is necessary to rethink from scientific perspective and adjust the policy of countering threats of global and regional economic and social contradictions. International discussions on the plans for the post-war reconstruction of Ukraine prove the still uncertain, extremely multidimensional picture of the development of various components of the national socio-economic system. The amount of external financial support will depend on whether the measures to improve PFM during the period of martial law, as well as post-war reconstruction, will be interconnected, subordinated according to the space-time vector, etc. Conclusions. International financial institutions provide resources to conflict-prone and fragile states not only to correct imbalances, but also to build confidence during crisis situations when countries risk losing their ability to borrow on open markets. Taking into account the escalation of the geopolitical conflict associated with the full-scale Russian invasion of Ukraine, transformations in the fiscal sphere should be aimed at winning the war, preserving the territorial integrity of the state, supporting economic sovereignty and combating corruption, stimulating investment processes in the post-war recovery.