We consider some issues of correlation between the theory of public law and civil law in the aspect of legal regulation of relations in the sphere of public private partnership. We analyze the definition of the concept of the agreement on public private partnership, we comprehend the issues of interaction and legal status of the participant of public private partnership, on the basis of the analysis of certain normative-legal acts of the subjects of the Russian Federation and their comparison with the budget legislation, we draw conclusions about the public nature of agreements in the field of public private partnership. We illustrate statistical information on the development of public private partnership in the subjects of the Russian Federation, identify a number of factors that determine the positive effect of interaction between the participants of public private partnership, to which we refers to the development of the institutional environment in the field of public private partnership, the quality level of legal support, improving the experience of implementing public private partnership projects. It is stated that the development of the Institute of public private partnership is essential for the economy of the country as a whole and for regions and municipalities in particular. At the same time, it is impossible to conclude public agreements without the will of the state represented by the relevant authorities. In addition, mentioning the role of private interest, it is noted that in the case of the subjects of the Russian Federation, private partners enter into relations enshrined in the laws of the subjects of the Russian Federation, where the possible forms of participation of the subject in public private partnership are clearly defined, which in a sense limits the freedom of private partners.