We　introduced　two　continuous-wave　terahertz　iterative　phase-contrast　imaging　methods.　In-line　digital　holography　has　the　capability　to　reconstruct　the　amplitude　and　phase　distributions　simultaneously.　It　is　a　non-destructive,　high-resolution,　full-field　dynamic　phase-contrast　imaging　technique.　Ptychography　can　reconstruct　the　complex　amplitude　distribution　of　the　transmission　object　from　the　overlapped　diffraction　patterns.　Both　methods　can　achieve　phase-contrast　imaging,　and　are　suitable　for　terahertz　region.　In　this　paper,　both　Gabor　in-line　holographic　and　ptychographical　configurations　are　investigated　from　algorithms　to　experiments.　For　in-line　holography,　the　use　of　extrapolation,　synthetic　aperture,　sub-pixel　shifting　and　multi-plane　imaging　are　introduced　to　improve　the　resolution　and　reconstruction　accuracy.　For　ptychography,　we　obtained　the　ptychographical　reconstruction　results　of　a　polypropylene　alphabet　sample,　which　provides　a　new　imaging　method　for　terahertz　phase-contrast　imaging.