Abstract: Fly ash powder which was ground to different size was mixed with Portland cement in different proportions. Optimal particle size distribution (with maximum bulk density) was obtained according to Dinger-Funk Equation, and actual particle size distributions of each fly ash cement were calculated based on the testing results made by LS-230 granulometer. The relationships between particle size distribution and Dinger-Funk bulk density were investigated by grey connection analysis method.The properties of fly ash cement samples were tested in order to show the theory analyses. The results indicated that fly ash cement may have better properties than that of theory bulk density when the value of grey connection is higher between these two conditions.