Solid surfaces subjected to energetic ion bombardment generally develop chara-cteristic structures, which may significantly change total and differential sputtering yields. The change is due to several competing effects, for instance, change of the effective projectile incidence angle, recapture of obliquely ejected particles (shadow effect), and element local-enrichment in different micro-region on the alloy surface. From these, we have now developed an efficient new theoretical method for covering all of the above effects exactly. This method and its application to the analysis of experimental results of element (Cd) and alloy system (ＡｌxSn１００－x)targets are de-scribed in detail.