An　??-Fe　???　??-Fe　phase　transformation　occurs　in　iron　when　the　shock　loading　pressure　exceeds　13　GPa,　but　all　the　??-Fe　will　reverse　back　to　??-Fe　during　unloading,　resulting　in　no　residual　??-Fe　in　the　unloaded　samples.　To　prove　the　occurrence　of　this　process,　a　series　of　microstructural　characterization　techniques　were　used　to　study　the　microstructures　of　shock-loaded　iron,　but　hard　to　reach　a　consensus　on　the　experimental　results.　Here,　by　using　two　conventional　electron　microscopy　techniques,　electron　backscattered　diffraction　(EBSD)　in　scanning　electron　microscopy　and　selected　area　electron　diffraction　(SAED)　in　transmission　electron　microscopy,　we　reveal　six　novel　phase　transformation　variants　directly　related　to　the　reversible　phase　transformation.　On　this　basis,　the　essential　differences　of　microstructure　between　deformation　area　and　phase　transformation　area　are　revealed.　Further,　we　propose　two　fast　and　efficient　methods　which　can　identify　the　occurrence　of　the　reversible　phase　transformation　by　EBSD　and　SAED,　respectively.　The　universality　of　these　methods　has　been　verified　in　different　shock　loading　experiments　in　iron.