Biomass direct combustion power generation is the most simple but effective way in dealing with environmental issues and energy crisis. A comprehensive diagnosis with accurate evaluation of energy saving potential of a given biomass power plant is of great importance in lowing the cost of generating electricity, reducing the consumption of energy and pollutant emissions . This paper throws light upon an innovative energy consumption diagnosis method-the specific consumption analysis theory, which is based on the First and Second law of thermodynamics [2,3]. Taking a given biomass power plant of National Energy Group as an example, mathematical models are made based on all the components and processes. The specific consumption analysis theory is employed to calculate the specific consumption within the biomass power plant using design parameters under design operating conditions, thus demonstrating the specific consumption distribution in the power plant, which provides theoretical basis for energy-saving and optimization in biomass power plant.