A　phase　shifting　digital　holography　with　pre-magnification　is　designed.　In　order　to　fully　utilize　the　bandwidth　of　the　camera,　a　four-step　phase-shifting　digital　holography　is　adopted　to　retrieve　the　complex　distribution　of　the　object.　To　further　enhance　the　resolution　of　the　reconstructed　image　without　phase　aberration,　two　microscope　objectives　(MOs)　are　placed　in　front　of　the　object　and　the　reference　mirror.　The　MO　in　the　reference　arm　provides　parallel　beam　at　the　PZT　plane　thus　improve　the　precision　of　the　phase　shifting.　A　1951　USAF　negative　resolution　target　is　used　as　the　sample.　Experiment　result　demonstrates　the　feasibility　of　the　proposed　method.