The article deals with debatable issues of the system of regulation of social relations. The study is based on the principle of dualism of regulation of private relations, division of regulation into legal (self-regulation) and normative. It is noted that the nature of social relations, which are the subject of legal and regulatory regulation, is determined not so much in legislative provisions, only indirectly reflecting their nature, but by the direct nature of human activity, as an independent activity of the individual, carried out by him at his own risk in order to meet his needs through the choice of a suitable variant of behavior. The system of private relations determines the system of law, i.e. a certain set of its branches, distinguished by the peculiarities of the manifestation of the subject of regulation: personal non-property law, property law, law of obligations, inheritance law. The system of private relations is indirectly reflected in legislation as an external form of expression of the system of law. The system of law consists not only of homogeneous rights (branches of law), but also of other subdivisions of law that are not subject divisions of law: business law, corporate law, intellectual property law, family law, housing law, labor law, land law, etc. Such types of private rights, being sub-branches or institutions of law, belong simultaneously to several branches of law (personal non-property law, property law, law of obligations, inheritance law), but are distinguished by any special feature (signs) of regulated attitude: by subject, for example, business law; on the object, for example, housing law, etc .; on a special combination of elements regulated by relations, for example, intellectual property law, private international law; some other sign. The methodology used to study social relations, their legal forms and public organization will further clarify more specific problems.