Fly ash was super-pulverized into different fineness.The fineness of fly ash was tested with Blaine permeability apparatus.The micro-morphology of fly ash was analysed by SEM.The relationship between the fineness of fly ash and cement and the properties of the mortar was quantitatively studied by the method of grey incidence analysis.The results show that the key step to compound HPC(high performance concrete) is to select the cement and fly ash with ex-(cellent) morphology.The measure to properly improve the fineness of fly ash and reduce the fineness of cement could make the concrete gain the higher compressive strength and flexural strength.The measure to properly improve the fineness of fly ash could reduce the water requirement and improve the fluidity of concrete.