Abstract: Three-segment rockslide is a kind of unique mode from deformation to failure of a slope. Based on a 2-D geomechanics loading system, the physical simulation of the whole process from deformation to failure of the three-segment slide is accomplished. Displacement of the head and foot of the slope is tested with the laser displacement system. The experimental results indicate that the displacement monitoring curve generally shows the sudden brittle failure after the energy accumulation and stress adjustment. Because of the creep deformation of weak intercalation, the stage of creep consists of the initial deformation, the constant velocity deformation and the acceleration deformation just like that of a soil landslide. The stage of edge cracking is the most short-lived deformation stage, the displacement monitoring curve of which shows a “W” type change trend of “minus - increase-decrease-increase”. The locking section is the key of the stability of the rockslide, the foot of which is sheared after the top of which is sheared. Repeatedly, the damage deformation is progressive from the edge to the middle part. Eventually, the locking section is suddenly cut off. As a result, rockslide starts at a high speed.