The article analyzes the legal regulation of financing the solidarity system of compulsory state pension insurance. It is established that the main financial burden in the pension system of Ukraine lies at the solidarity level of pension provision. It has been found that the solidarity pension system is unable to properly perform the priorities assigned to it, and is solvent only through financial support from the state, which negatively affects other social spheres: health, culture, education, science, etc. The author analyzes the incomes of the Pension Fund of Ukraine, which are divided into its own funds and the additional funds. Own source revenues are funds received from enterprises, institutions and individuals, as mandatory and voluntary contributions, as well as income from investments and income from financial sanctions for violations of current pension legislation. And additional funds are transferred to the Pension Fund of Ukraine from the State Budget of Ukraine, as well as from state trust funds. It has been established that in connection with the spread of COVID-19 on the territory of Ukraine, the state has provided measures to exempt certain categories of payers of the single social contribution from its payment. It is substantiated that the legally defined sources of budget formation and mechanisms of their accumulation do not contribute to a rapid increase in revenues to the Pension Fund of Ukraine and improve the level of pensions, so it is urgent to unload the solidarity level of mandatory state pension insurance and introduce accumulative level. It has been proved that the reform of the pension system of Ukraine should be aimed at minimizing the degree of dependence of the pension system of Ukraine on the solidarity level of pensions, because in modern conditions the joint responsibility of generations, which was relevant and effective in Soviet times, cannot effectively solve the problem of pensions, taking into account the development of unfavourable trends in demographic processes, rising unemployment, low wages, the formation of shadow payroll funds to distrust people’s pension system in Ukraine as such, as well as legal illiteracy in this area.