The invention discloses a monitoring method for internal deformation of a high rock-fill dam, in particular to a monitoring method for monitoring dam surface settlement through horizontal arrangementand monitoring dam deep displacement through vertical arrangement. The arrangement of array displacement meters can play a role in monitoring the displacement of a dam in the horizontal direction in ariver direction, a transverse river direction and a vertical direction and the deep displacement in the vertical direction, and the monitored data information is perfect. Compared with a previous dammonitoring instrument layout method, the layout method is simple in operation, detailed in obtained data, free of maintenance for a long time, wide in application range and capable of being used forhigh dams of 200m or above. The measuring device arrangement method is beneficial to the development of dam displacement monitoring in the field, and is beneficial to the promotion of research on damdisplacement monitoring basic theories.