An　atomic　force　microscopy　image　is　a　dilation　of　the　specimen　surface　with　the　probe　tip.　Tips　wear　or　are　damaged　as　they　are　used.　And　AFM　tip　shape　and　position　status　make　AFM　images　distorted.　So　it　is　necessary　to　characterize　AFM　tip　shape　and　position　parameters　so　as　to　reconstruct　AFM　images.　A　geometric　model-based　approach　is　presented　to　estimate　AFM　tip　shape　and　position　status　by　AFM　images　of　test　specimens　and　scanning　electron　microscope　(SEM)　images　of　AFM　tip.　In　this　model,　the　AFM　tip　is　characterized　by　using　a　dynamic　cone　model.　The　geometric　relationship　between　AFM　tip　and　the　sample　structure　is　revealed　in　linewidth　and　profile　measurement.　The　method　can　easily　calculate　the　tip　parameters　including　half-cone　angle,　installation　angle,　scanning　tilting　angle　and　curvature　radius,　and　easily　estimate　the　position　status　of　AFM　tip　when　AFM　tip　moves　on　the　specimen.　The　results　of　linewidth　and　profile　measurement　are　amended　accurately　through　this　approach.　Copyright　©　2011　American　Scientific　Publishers　All　rights　reserved.