The article examines the issue of the legal nature and methodology of property rights assessment as a tool for implementing the public function of the state. The subjective composition of the assessment participants in the administrative-legal sphere is considered, as well as the issue of procedural legitimacy of decisions made on the basis of the assessment results. Doctrinal approaches to the normalization of mechanisms of administrative control over the assessment of property rights in the public interest are proposed. The article also examines the legal nature of property rights assessment as a tool for implementing the public functions of the state in the context of administrative law. It is substantiated that modern assessment activity is not exclusively an economic-legal or business institution, but acquires the features of a public service, an administrative tool and an element of a power procedure. This is especially relevant in the context of using the assessment results in administrative regulation - taxation, management of state and municipal property, social security, judicial proceedings, and the performance of functions of executive bodies. The author investigates the methodological principles of forming an assessment within the framework of public-legal procedures, in particular, its dependence on administrative regulation, standards, the principle of objectivity, transparency, stability and a non-discriminatory approach to the results. The legal status of entities that carry out or order an assessment in the public sector is analyzed, including executive bodies, local governments, self-government of assessment entities and independent evaluators as delegated entities of public competence. The article also focuses on the category of procedural legitimacy of assessment: its meaning, features, risks of administrative intervention, the presence of mechanisms for checking, verifying and appealing. The features of assessment as a component of the administrative process that should be regulated from the standpoint of administrative-procedural law are separately disclosed. The emphasis is placed on the need to create a single administrative regulation of assessment activities in public administration, improve procedures for protecting the rights of subjects, standardize verification tools and increase the professional responsibility of evaluators. It is concluded that the assessment of property rights in the field of public law requires not only economic accuracy, but above all, legal certainty, institutional transparency, and procedural fairness as the foundations of democratic administrative governance.