Public Function ClipRasterByPolgon(pInGeoDataset As IGeoDataset, pPolygon As IPolygon) As IRaster
    Dim pRaster As IRaster
    If TypeOf pInGeoDataset Is IRasterLayer Then
        Dim pRasterlayer As IRasterLayer
        Set pRasterlayer = pInGeoDataset
        Set pRaster = pRasterlayer.Raster
    ElseIf TypeOf pInGeoDataset Is IRasterDataset Then
        Dim pRasterDataset As IRasterDataset
        Set pRasterDataset = pInGeoDataset
        Set pRaster = pRasterDataset.CreateDefaultRaster
    ElseIf TypeOf pInGeoDataset Is IRaster Then
        Set pRaster = pInGeoDataset
    Else
        Exit Function
    End If

    Dim pInputDataset As IGeoDataset
    Set pInputDataset = pRaster

    Dim pExtractionOp As IExtractionOp
    Set pExtractionOp = New RasterExtractionOp
    Dim pRasterAnalysisEnvironment As IRasterAnalysisEnvironment
    Set pRasterAnalysisEnvironment = pExtractionOp
    pRasterAnalysisEnvironment.SetCellSize esriRasterEnvValue, GetRasterCellSize(pRaster)
    pRasterAnalysisEnvironment.SetExtent esriRasterEnvValue, pPolygon.Envelope

    Dim pOutputDataset As IGeoDataset
    Set pOutputDataset = pExtractionOp.Polygon(pInputDataset, pPolygon, True)

    Set ClipRasterByPolgon = pOutputDataset
End Function

Public Function GetRasterCellSize(pRaster As IRaster) As Double
    Dim pProps As IRasterProps
    Set pProps = pRaster
    GetRasterCellSize = pProps.MeanCellSize.X
End Function

注意：pPolygon 的ISpatialReference要与RASTER的一样如果不一样，可以使用
pGeometry.Project pRasterSpatialReference来设定