Regulation　of　the　mechanical　properties　of　proteins　plays　an　important　role　in　many　biological　processes,　and　sheds　light　on　the　design　of　biomaterials　comprised　of　protein.　At　present,　strategies　to　regulate　protein　mechanical　stability　focus　mainly　on　direct　modulation　of　the　force-bearing　region　of　the　protein.　Interestingly,　the　mechanical　stability　of　GB1　can　be　significantly　enhanced　by　the　binding　of　Fc　fragments　of　human　IgG　antibody,　where　the　binding　site　is　distant　from　the　force-bearing　region　of　the　protein.　The　mechanism　of　this　long-range　allosteric　control　of　protein　mechanics　is　still　elusive.　In　this　work,　the　impact　of　ligand　binding　on　the　mechanical　stability　of　GB1　was　investigated　using　steered　molecular　dynamics　simulation,　and　a　mechanism　underlying　the　enhanced　protein　mechanical　stability　is　proposed.　We　found　that　the　external　force　causes　deformation　of　both　force-bearing　region　and　ligand　binding　site.　In　other　words,　there　is　a　long-range　coupling　between　these　two　regions.　The　binding　of　ligand　restricts　the　distortion　of　the　binding　site　and　reduces　the　deformation　of　the　force-bearing　region　through　a　long-range　allosteric　communication,　which　thus　improves　the　overall　mechanical　stability　of　the　protein.　The　simulation　results　are　very　consistent　with　previous　experimental　observations.　Our　studies　thus　provide　atomic-level　insights　into　the　mechanical　unfolding　process　of　GB1,　and　explain　the　impact　of　ligand　binding　on　the　mechanical　properties　of　the　protein　through　long-range　allosteric　regulation,　which　should　facilitate　effective　modulation　of　protein　mechanical　properties.