Moscow Economic Forum (MEF-2016, end of March, 2016) had discussion on the intriguing theme of search for new ideas of development of the Russian economy, with the national idea as the main focus. Such orientation of scientific search makes it reasonable to turn to cognitive potential of Lev Gumilev’s theory of passionarity. Its potential is being developed in many directions of modern social science. Application of method of the theory of passionarity shows its relevance for the Russian economic science, in particular, for the process of collective search for new ideas which could help to renovate the archaic structure of Russian economy. The author justifies legitimacy, relevance and necessity of application of methodological tools of the theory of passionarity for the analysis of creative potential of the Russian ethnos at the current life cycle phase. Application of these tools can provide efficiency of search for the new ideas of Russian economic development, and result in a denial of various clich é s which may mislead the scientific search. At the same time, today such application is limited because of the methodological abilities of research participants, due to decline in political-economy level of analytical culture. Special attention is paid by the author to the interdisciplinary character of search for the new ideas of Russian economic development, with the emphasis on complex approach, involving: context analysis, detailed historical description of the economic system, clearness of the research in terms of its object, conceptual integrity, effective combining of strengths of different scientific approaches, as well as assessment of feasibility of the new developmental ideas. The author seeks the real assessment of potential of development that the Russian ethnos possesses at the inertia phase of its life cycle.