Abstract: The gray correlation analysis is one effective tool for quantification comparing the important degree of each influence factor.Firstly, the principle of gray correlation analysis and the calculation of gray correlation matrix is introd-uced; Secondly, the blasting quality experiments were did in the one mine and one quarry of Nanning, the experimental datas is taked as the samples , and the primary and secondary order of factors that influence blasting block is workd out. The calculational results show that , the crude unalterable factors play a primary control role in blasting block,the crude unalterable factors are rock cranny,the subjective alterable factors play a secondary control role, the subjective alterable factors are dynamite unit consumption、hole distance、row distance. The blasting block can be controlled through controlling the subjective alterable factors, the large block rate decreased 4%～8% after adjusting the blasting parameters in mine, the effect is obviously,so the gray correlation analysis inaugurates a simple and effective approach for determining the important degree of each influence factors.

Key words: blasting quality, grey correlation analysis, influence factors, block distribution, important degree