Under　long-term　uneven　loading,　joint　surfaces　between　the　components　of　heavy-duty　machine　tools　become　inclined　owing　to　both　external　loads　as　well　as　the　heavy　weight　of　the　machinery　itself.　In　this　study,　to　reconstruct　the　real　contact　parameters　at　certain　angles　of　inclination,　the　macro　contact　angle　was　first　converted　into　a　micro　contact　angle　based　on　the　stress　characteristics　and　the　deformation　of　asperities　were　considered.　The　real　contact　surface　area　was　then　calculated　using　piecewise　integration　according　to　three　stages　deformation:　elastic,　elastoplastic,　and　completely　plastic.　A　stiffness　model　of　the　joint　surface　was　derived　according　to　classification　theory.　Finally,　an　experimental　system　with　inclinations　between　the　joint　surfaces　was　built　and　used　to　validate　the　model　by　comparing　theoretical　and　experimental　mode　values.　The　present　paper　analyzes　the　influence　of　different　fractal　parameters,　inclination　values,　and　other　important　parameters　on　the　characteristics　of　the　joint　surface　using　the　proposed　fractal　model　and　provides　a　theoretical　basis　for　improving　the　design　and　precision　of　heavy-duty　CNC　machine　tools.