As　most　of　the　Computer　Aided　Tolerancing　tools　can　only　deal　with　the　CAD　models　with　an　ideal　surface　and　can　not　reflect　manufacturing　errors　in　physics　and　geometry,　this　paper　explores　a　multi-scale　representation　method　for　skin　model　shapes　in　the　Geometrical　Product　Specification.　A　discrete　data　modeling　method　was　proposed　for　the　simulation　of　topographic　errors　of　surfaces　and　section　profiles　of　a　product　in　macroscopic　and　microcosmic　scales　based　on　new-generation　geometrical　product　specification.　Firstly,　a　simulation　method　for　multi-scale　surface　topographic　errors　based　on　discrete　wavelet　was　presented.　Then,　discrete　wavelet　was　used　to　simulate　multi-scale　surface　topography　errors　for　sampling　data　of　the　surfaces　and　section　profiles　of　a　part.　Finally,　multi-scale　surface　topography　errors　were　composed　and　skin　models　for　two-dimentional　profile　and　three-dimentional　surface　were　acquired.　The　simulation　and　experiment　results　show　that　the　proposed　method　represents　skin　models　with　multi-scale　surface　topographic　errors　and　the　average　relevant　error　between　the　results　of　Ra　obtained　by　a　white-light　interferometer　and　the　proposed　simulation　method　is　less　than　4%.　The　results　verify　the　correctness　and　applicability　of　the　proposed　method,　and　provide　a　valid　way　for　more　comprehensive　representation　of　skin　model　in　new-generation　geometrical　product　specification.　©　2016,　Science　Press.　All　right　reserved.