The invention relates to a geological slumped mass monitoring technology, in particular to a slumped mass geological hazard mass monitoring method based on the three-dimensional laser scanning technology. Geological hazard zones are divided into an isolated type, a convex type and a concave-convex alternate type through a three-dimensional laser scanner according to different geomorphological features, and point, line and plane (body) monitoring data is extracted for analysis according to the distance between sampling and simplifying points monitored at different distances in different scanning modes; the change rate (horizontal and vertical), the displacement deformation and the displacement resultant vector direction are calculated according to change rules, and the change of a slumped mass is quantitatively analyzed.