The　success　of　orthopedic　implants　depends　on　the　sufficient　integration　between　tissue　and　implant,　which　is　influenced　by　the　cellular　responses　to　their　microenvironment.　The　conformation　of　adsorbed　extracellular　matrix　is　crucial　for　cellular　behavior　instruction　via　manipulating　the　physiochemical　features　of　materials.　To　investigate　the　electrostatic　adsorption　mechanism　of　fibronectin　on　nanotopographies,　a　theoretical　model　was　established　to　determine　surface　charge　density　and　Coulomb＇s　force　of　nanotopography　-　fibronectin　interactions　using　a　Laplace　equation　satisfying　the　boundary　conditions.　Surface　charge　density　distribution　of　nanotopographies　with　multiple　random　fibronectin　was　simulated　based　on　random　number　and　Monte　Carlo　hypothesis.　The　surface　charge　density　on　the　nanotopographies　was　compared　to　the　experimental　measurements,　to　verify　the　effectiveness　of　the　theoretical　model.　The　model　was　implemented　to　calculate　the　Coulomb＇s　force　generated　by　nanotopographies　to　compare　the　fibronectin　adsorption.　This　model　has　revealed　the　multiple　random　quantitative　fibronectin　electrostatic　adsorption　to　the　nanotopographies,　which　is　beneficial　for　orthopedic　implant　surface　design.Significance:　The　conformation　and　distribution　of　adsorbed　extracellular　matrix　on　biomedical　implants　are　crucial　for　directing　cellular　behaviors.　However,　the　Ti　nanotopography-ECM　interaction　mechanism　remains　largely　unknown.　This　is　mostly　because　of　the　interactions　that　are　driven　by　electrostatic　force,　and　any　experimental　probe　could　interfere　with　the　electric　field　between　the　charged　protein　and　Ti　surface.　A　theoretical　model　is　hereby　proposed　to　simulate　the　adsorption　between　nanotopographies　and　fibronectin.　Random　number　and　Monte　Carlo　hypothesis　were　applied　for　multiple　random　fibronectin　simulation,　and　the　Coulomb＇s　force　between　nanoconvex　and　nanoconcave　structures　was　comparatively　analyzed.　Graphical　abstractIn　the　macroscale,　the　combination　between　bone　tissue　and　implant　is　dominated　by　the　cellular　responses　to　their　microenvironment,　which　are　initially　influenced　by　the　cell　-　extracellular　matrix　(ECM)　interactions.　The　ECM　adsorption　on　nanoscale　Ti-topography　is　dominated　by　the　Coulomb＇s　force,　we　proposed　a　theoretical　model　to　simulate　multiple　random　fibronectin　adsorption.