The article examines the forms of parliamentary activity and powers of deputies directly related to the constitutional goal of realizing mandate of national confidence. Legislative regulation of forms of the activity has changed more than once, therefore differentiated approaches to understanding the system of forms of deputy activity appeared. The purpose of the study is to classify and systematize the forms of deputy activity. Its forms can be divided into loyal and oppositional, basic (fundamental) ones and control. The basic forms of activity of national representatives include: interaction with voters, participation in meetings of a representative body. Control forms of activity of deputies include interpellation, non-confidence vote, resolution of censure, parliamentary investigation. Within the framework of the study, the author determines the type of constitutional and legal norms establishing the powers and forms of activity of deputies. The norms on the powers of the people’s representatives are usually substantive, while the norms defining forms of deputy activity predetermine their free political activity aimed at realizing mandate of popular confidence. The result of analysis of powers and forms of parliamentary activity at the federal level of public power is the conclusion about ensuring the mandate of popular trust through visits and participation in the work of collegial bodies of state power. At the same time, author draws attention to the need to eliminate the inaccuracies that have arisen in the legislative regulation of the concepts of “participation in meetings” and “participation in work”. As a result of the study, author formulates a conclusion about the need to differentiate concepts of the form of deputy activity and of deputies powers, emphasizing their differences, including by comparing the individual powers of parliamentarians not related to the expression of public power. These include participation in the execution of instructions from the chambers, organization of parliamentary hearings, submission of a parliamentary or deputy inquiry, and addressing questions to members of the Government. The author notes weakening of the deputy’s request role as a control mechanism, its transformation into an official appeal to other officials. In turn, addressing a question to a member of the Government of the Russia acquires control functions. Accordingly, the democratic nature of constitutionalism, among other things, is predetermined by a sufficient variety of individual and collective forms of parliamentary work, which should be very extensive.