The　deformation　mechanisms　of　twin-structured　metallic　materials　have　attracted　great　interest.　Though　previous　theoretical　predictions　have　suggested　that　the　repulsive　force　of　the　twin　boundary　(TB)　can　significantly　affect　the　deformation　of　twin-structured　metals,　it　remains　unclear　whether　this　prediction　applies　to　experimental　conditions.　In　this　paper,　the　atomic-scaled　deformation　process　of　twin-structured　Pt　nanocrystals　was　in　situ　observed　using　our　home-made　device　in　a　high-resolution　transmission　electron　microscope.　We　have　shown　that　the　plastic　deformation　of　the　twin-structured　Pt　nanocrystals　was　governed　by　full　dislocation　generation　as　well　as　Lomer　dislocation　(LD)　lock　formation　and　destruction.　After　LD　locks　were　destructed,　these　full　dislocations　tended　to　move　towards　the　surface　of　the　nanocrystals.　The　findings　revealed　that　due　to　the　ultra-high　repulsive　force　of　TB　on　dislocation,　there　was　no　dislocation-TB　reaction　during　the　deformation.　These　findings　can　enrich　our　understanding　of　the　dislocation　behaviors　of　twin-structured　nanocrystals.