The "principle of ultimate efficiency equilibrium" is the theoretical discovery and contribution of Liu Haofeng, the founder of China's "harmonious theory", in his fifth volume of Principles of Economic Science, i.e. Ideological System of Harmonious Theory in 2010. It is a necessary supplment and development and a great transition for the “principle of maximum benefit distribution”, which is the theoretical contribution made by Professor Mao Yushi, a famous Chinese economist, in the field of microeconomics.