According　to　the　definition　of　tacit　knowledge　and　characteristics　of　its　transfer,　a　differential　dynamic　model　is　established　for　describing　tacit　knowledge　transfer　of　an　organization　by　its　external　learning.　Furthermore,　the　main　parameters　influencing　the　asymptotic　solution　of　the　transfer　process　are　analyzed.　The　model　proposed　in　this　paper　depicts　the　tacit　knowledge　transfer　law　of　an　organization　by　its　external　learning,　points　out　the　conditions　that　an　organization　obtains　external　tacit　knowledge　and　the　conditions　that　tacit　knowledge　is　diffused　in　the　organization,　at　the　same　time,　some　approaches　to　improve　the　efficiency　of　the　tacit　knowledge　transfer　are　also　put　forward.　Finally,　the　management　implication　of　this　model　is　illuminated.