Terahertz　(THz)　continuous-wave　digital　holography　is　an　advanced　interference　imaging　technique　that　can　reconstruct　quantitative　distributions　of　amplitude　and　phase　of　the　sample　in　real　time　with　high　resolution.　In　this　paper,　a　reflective　off-axis　holographic　system　is　presented.　A　Gaussian　Fitting　method　is　applied　to　enhance　the　hologram　contrast　and　Laplacian　of　Gaussian　filter　is　used　to　obtain　the　reconstructed　distance　automatically.　Furthermore,　spectrum　filtering　method　and　angular　spectrum　algorithm　are　used　to　obtain　the　complex　amplitude　of　the　One-Yuan　Chinese　metal　coin.　The　results　confirm　the　prospective　application　of　terahertz　digital　holography　in　the　surface　morphology　for　reflective　samples.