The　nanocrystalline　Ni　thin　films　with　high　density　nano-scale　growth　twins　were　synthesized　by　direct　electrodeposition　technology.　The　five-fold　twinning　structure　in　electrodeposited　nano-twin　Ni　was　systematically　investigated　by　TEM.　The　remarkable　diffraction　pattern　and　HRTEM　images　obtained　from　the　cross-section　observation　demonstrate　directly　that　the　electrodeposited　nano-twin　Ni　has　five-fold　twinning　structure　with　five　{111}　twinned　subcrystals　and　systematically　analyzed　the　7.35　degrees　intrinsic　structural　gap.　In　this　work,　the　7.35　degrees　gap　was　at　least　inset　in　two　twin　boundaries　of　the　five-fold　twin,　the　twin　boundaries　which　share　the　7.35　degrees　gap　always　broaden　and　was　decomposed　into　other　twins,　so　that,　the　grain　present　a　irregular　shape.　cross-sectional　TEM　micrograph　revealed　that　the　electrodeposited　nano-twin　Ni　had　columnar　grain　structure　with　a　strong　{110}　texture.　By　means　of　comprehensive　structure　characterization,　a　new　space　structural　model　of　the　five-fold　twin　was　proposed.