An apparatus for compensating for a beam angle of a multi-layer LiDAR includes: a beam angle calculation unit configured to calculate a distance d calculated by using ground data detected by a ground data detection unit and a beam angle of the multi-layer LiDAR by using a mounting height of the multi-layer LiDAR stored in a storage unit. When the beam angle calculated by a beam angle calculation unit is in a threshold range, a beam angle selection unit selects the calculated beam angle as the beam angle, when a beam angle compensation unit compensates for the initial beam angle by using the beam angle selected by the beam angle selection unit.