Multiple　factors,　such　as　crystallographic　orientation,　twins,　dislocation,　and　grain　size,　significantly　affect　the　tensile　properties　of　alloys;　however,　it　is　difficult　to　identify　the　dominant　factor　from　only　the　initial　and　final　conditions.　To　mitigate　this　limitation,　a　combination　of　in　situ　tensile　technique　and　electron　backscattering　diffraction　(EBSD)　was　used　to　analyze　the　dominant　factors　affecting　the　tensile　properties　of　pure　nickel　during　the　stretching　process　at　different　annealing　temperatures.　This　process　consists　of　two　parts.　The　first　is　the　analysis　of　the　dominant　factor　candidate　from　the　initial　alloy　condition.　The　second　part　is　the　confirmation　step　that　uses　the　in-situ　EBSD　tensile　technique　via　real-time　analysis　of　the　microstructural　transformation　during　plastic　deformation　while　measuring　the　tensile　properties.　Four　pure　nickel　samples　with　different　initial　states　and　mechanical　properties　were　tested　in　this　study.　Using　EBSD　characterization,　the　distribution　kernel　average　misorientation　gradually　concentrates　in　the　regions　of　accumulated　fine　grain　as　the　tensile　stress　proceeds.　The　grain　size　of　pure　nickel　was　confirmed　to　be　the　most　significant　factor　influencing　the　tensile　properties.　Our　results　reveal　a　feasible　evaluation　process　for　the　primary　effect　factor　of　the　tensile　properties　pure　nickel　owing　to　grain　size.