Abstract: Stearic acid was found effective as a milling aid in the ball milling of attapulgite. Stearic acid milled attapulgite could be finely dispersed in polyurethane leather without re-agglomeration, which was confirmed by SEM observation. the polyurethane leather containing 10 wt % such treated attapulgite satisfied the requirement of }B 1646-92. When the content of stearic acid milled attapulgite was 1 wt % , the radial and latitudinal tensile strengths of polyurethane leather were 149.8 N and 151.4N，tearing strength 35. 7 N and 53.3 N, elongation at break 331.9%and 118.3%，respectively. the improvement of mechanical performance of the polyurethane leather could be attributed to the interaction between stearic acid milled attapulgite and polyurethane.

Key words: attapulgite, polyurethane leather, milling aid, filling