| The multiple boundary conditions and coupling problem of energy efficiency index brings new challenges to the depth of theoretical studies of energy-saving of coal-fired power unit. The key points of the energy saving and optimization of coal-fired power units lie in the determination of the reference state of the coal-fired power unit. At present, the target value of the key energy efficiency index of the coal-fired power unit is usually determined by the design value of the unit, the calculation value of the variable working condition or the value of the coal-fired test. Each target value determination method has its limitation, with change of the unit operation condition and performance of the equipment state, target values have been unable to match the unit of the actual running state, making operation instruction limited and can not found the real reason of the reduction of energy efficiency.The data mining method based on the massive historical data of steam turbine unit can well match the actual state of the unit, so it can well determine the actual energy efficiency index of the target condition. In view of the complex boundary conditions, the problem of multiple and coupling energy efficiency index and difference in energy efficiency index.In this paper, based on fuzzy c-means clustering, grey correlation reduction and with the subjective AHP analysis method and entropy method combined combination weighting method of data mining to extract the actual target value of the energy efficiency index under the target condition. But based on data mining to get the target value of energy efficiency index is limited by operation boundary conditions and the actual equipment condition, mainly reflecting the level of operation level of the operator, and does not reflect the objective conditions of equipment performance reference state. The further construction of the equipment performance index related to the physical model, to get mining reflect the device performance energy efficiency index is modified, finally get the reference state of the steam turbine unit key energy efficiency characteristic variables, To provide basis for energy consumption analysis and energy saving diagnosis of steam turbine generator under different operating conditions.Finally, based on the state of energy efficiency index after data mining, the paper analyzes the main energy efficiency indexes which affect the energy consumption of a 600MW steam turbine unit through sensitivity analysis, optimization knowledge base based on energy efficiency index, the optimization and adjustment of energy consumption index of guidance, and ultimately achieve to improve unit efficiency level. |