The preferential sputtering of the ternary alloy system Cu76Ni15Sn9 has been studied under 27keV argon ion bombardment at normal incidence using collection film technique combined with Auger electron spectroscopy analysis. After sputtering target surface was examined in a scanning electron microscope, and the surface composition was measured with electron probe microanalyser for topographical features of different micro-region surface. The experimental results showed that the preferred ejection of Cu atoms compared with Ni atoms and of Ni atoms compared with Sri atoms take place over the whole range of the measured ejection angle (0-600). The influence of the topographical features and "locally rich element" phenomenon on the ejection atoms are discussed.