In order to substantiate the principles of improvement of the institutional environment of the state social policy in Ukraine, the institutional features of the EU social policy development, including the post-socialist countries of Central and Eastern Europe that entered the EU, have been investigated. It has been determined that a single social model has not been formed yet, but it should be considered as a kind of code of conduct that ensures decent living standards and social development at all levels of public administration. On the basis of these values analysis, the principles of the functioning of the institutional mechanism of the state social policy of Ukraine have been specified.