The invention discloses a point-by-point scanning-based terahertz reflective type holographic imaging system and imaging method, belongs to the technical fields of an imaging method and an imaging system, and aims to solve the problem of phase information shortage in the conventional continuous terahertz wave confocal scanning imaging. Reference light is introduced to a confocal scanning system firstly; the reference light wave phase is dynamically changed in a mode of changing an optical distance by moving a planar reflector in a sample point-by-point scanning imaging process, and then synthesis of a beam of planar reverence light is performed equivalently; coherent intensity is recorded by a terahertz single-point detector so as to obtain an image surface hologram; and finally, an object amplitude and a phase reproductive image are obtained by adopting a conventional off-axis image surface hologram reconstruction algorithm.