Scratch　testing　is　widely　used　for　its　convenience　and　promise　but　lacks　analytical　or　semi-analytical　solutions　for　determining　the　mechanical　properties　of　materials.　In　this　paper,　by　investigating　the　scratch-induced　strain　field,　we　propose　a　semi-analytical　solution　for　the　forward　prediction　of　scratch　responses　and　inverse　characterization　of　plastic　parameters　of　metallic　materials.　The　solution　is　verified　through　finite　element　simulation　and　experimental　data　from　eight　different　metallic　materials.　The　results　indicate　that　the　method　is　precise,　with　an　average　error　of　5.25%　in　the　forward　prediction　of　scratch　forces　and　7.48%　in　the　inverse　characterization　of　plastic　parameters.　This　work　provides　a　solid　theoretical　foundation　for　using　scratch　tests　to　assess　material　plasticity.