The　microprocess　of　fracture　in　the　nanocrystalline　Ni　(nc-Ni)　with　grain　size　of　20-30　nm　synthesized　by　electrodeposition　was　investigated　by　in-situ　tensile　test　in　TEM.　The　results　show　that　many　dislocations　were　emitted　from　the　crack　tip　and　the　grain　boundaries　near　the　crack.　The　dislocations　traveled　through　the　grain,　and　most　of　them　annihilated　in　the　opposite　grain　boundaries.　The　grain　boundaries　in　nc-Ni　can　act　as　sources　and　sinks　for　dislocations.　Some　dislocations　might　pile　up　in　the　front　of　the　crack　tip　and　a　very　small　dislocation　free　zone　formed　between　crack　tip　and　the　pile-up　dislocations.　Nano-crack　might　initiate　at　the　crack　tip　that　made　the　main　crack　propagated　continuously.　Nano-crack　might　also　initiate　in　the　front　of　the　crack　and　then　connected　with　the　main　crack　that　made　the　main　crack　propagated　discontinuously.　A　thin　ribbon　zone　might　form　during　the　fracture　in　which　the　microcracks　initiated.　The　connection　of　cracks　in　the　ribbon　resulted　in　the　Zig-Zag　crack　propagation.