Based　on　the　Fresnel　diffraction　theory,　the　depth　of　view　(DOV)　and　the　depth　of　focus　(DOF)　of　the　digital　holographic　system　are　analyzed.　The　approximate　expressions　of　the　DOF　of　the　different　holographic　recording　configurations　are　deduced.　The　results　show　that　the　DOV　and　DOF　of　the　digital　holographic　imaging　system　are　related　to　the　optical　wavelength　and　the　numerical　aperture　of　the　CCD　camera　and　to　the　offset　of　the　reference　light　wave.　With　both　the　same　recording　distance　and　parameter　of　CCD,　the　DOF　of　the　off-axis　Fresnel　holographic　system　is　found　larger　than　that　of　the　in-line　Fresnel　digital　holographic　system.　The　DOF　of　off-axis　lensless　Fourier　digital　holographic　system　with　symmetrical　offset　of　reference　wave　is　slightly　smaller　than　that　of　the　system　without　symmetrical　offset.　Moreover,　in　digital　holographic　microscopy,　the　DOF　of　off-axis　lensless　Fourier　digital　holographic　system　is　larger　than　that　of　in-line　Fresnel　digital　holographic　system.　The　computer　simulation　results　confirm　the　validity　of　the　theoretical　analysis.