In this paper, the influences of abrasive size, abrasive concentration and admixture way on the abrasive dispersing of the sintered ultra-fine diamond tool were systemically investigated. Then, a comparison of the abrasive dispersing was made between the sintered ultra-fine diamond tool and the newly developed ultra-fine diamond tool by gel technique. ESEM was applied to observe the abrasive dispersing of the sintered and gel-coupled ultra-fine diamond tools. The abrasive dispersing was quantitatively evaluated by the statistic laws of grit spacing in a certain area. Experimental results indicated that the dispersing was mainly influenced by the abrasive size. The ultra-fine abrasive tended to agglomerate with the decrease of grit sizes due to the increase of surface energies. The abrasive concentration and admixture way had few effects on abrasive dispersing. The abrasive dispersing of the sintered diamond tool was worse compared with the gel-coupled ultra-fine diamond tool.