An automatic test system and method for mechanical parameters of surrounding rock applicable to a TBM. The system includes: an aggregate portion collecting a rock slag in a TBM tunneling process in real time; a gripping portion gripping any rock slag from obtained rock slags; a visual processing apparatus performing three-dimensional imaging for a rock slag under test in an infrared ranging manner; calculating positions of loading points for an abrasiveness test experiment, and determining, based on a spacing between loading points, whether rock slag under test meets a requirement; and determining actual positions of loading points if the rock slag under test meets the requirement, and determining a region, on a surface of rock slag, that meets a set condition as an action region for abrasiveness test experiment; and a rock abrasiveness test apparatus automatically performing an abrasiveness test for a rock slag under test that meets a requirement.