The　atomic　structures　of　specific　types　of　linear　defects　(phason　lines)　and　planar　defects　(phason　planes)　in　the　complex　metallic　alloy　phase　xi＇-Al-Pd-Mn　have　been　determined　by　high-resolution　electron　microscopy　(HREM)　and　theoretical　HREM　simulation.　The　results　show　that　a　representational　atomic　structural　model　for　phason　planes　can　be　constructed　by　introducing　a　shift　between　two　parts　of　the　perfect　crystalline　structure　using　a　translation　vector　of　r　=　(1/2)a　+　(1/2　tau)c.　This　typical　phason　plane　is　normally　parallel　to　the　(001)　plane　of　the　xi＇-Al-Pd-Mn　phase　and　consists　of　phason　lines,　which　are　arranged　side-by-side　with　their　linear　direction　parallel　to　the　[010]　axis.　HREM　simulations,　based　on　the　structural　model　for　both　edge-on　and　inclined　types　of　phason　lines,　agree　well　with　the　experimental　results.　Taking　into　account　the　fact　that　the　structural　difference　between　various　curved　phason　planes　arises　from　the　variation　in　the　arrangement　of　individual　phason　lines,　the　atomic　structures　of　the　edge-on　and　inclined　phason　lines　can　be　used　to　explain　the　various　curved　phason　planes　frequently　observed　in　the　xi＇-Al-Pd-Mn　phase.