Varied management activity requires correct use of legal factor. Legal imperatives are regarded in the article as obligatory regulators and normative guidelines. Unfortunately in theory and in practice law is connected with separate segments of administration. More correct view is that administration legal regulation is a system. Its constituent parts are definition of legal status of administration relations participants including their competence, putting procedures and regulations in practice, legal decision making such as acts, mechanisms of enforcement, legal valuation of administration and monitoring. Flexible use of legal imperatives promotes stability of administration system, flexibility and efficiency of administration.