Abstract: The degree of deviation of the particle size distribution(PSD) from the optimum PSD for 12 different samples of cement was calculated by gray relational analysis and fractal dimension evaluation in this paper. The results indicated that estimated results of particle size distribution evaluated both by gray relational analysis and fractal dimension evaluation are almost identical. In order to investigate the application of two methods comparatively in evaluating PSD, the relationship between the values of fractal dimension difference, the gray relational degrees and some properties of the testing cements was studied further. The result showed that the linear correlation between the values of fractal dimension difference and the properties of testing samples of cement was somewhat better than that between the gray relational degrees and the properties of testing samples of cement. That is, the application of fractal dimension evaluation was better than that of gray relational analysis in evaluating PSD to some extent. At last, the reason for the results was analyzed simply.