The invention discloses a loading plate device of a large-scale indoor true-triaxial physical simulation testing machine. The loading plate device consists of a loading plate, rope channels and a high-strength rope, wherein the loading plate includes the rope channels formed in the loading plate. The high-strength rope passes through the rope channels formed in the loading plate and is hung on a hook of an indoor crane, the loading plate is installed on the outer side of a sample, the high-strength rope is connected with the loading plate, the high-strength rope is connected to the loading plate through the rope channels before the high-strength rope is provided with the loading plate, and the high-strength rope is hung on the hook of the lifting crane. The loading plate device is simple in structure and convenient to use. The stability of the loading plate in the installing process is improved, and potential safety hazards of an indoor test are reduced. The loading plate device is suitable for an indoor true-triaxial physical simulation test and has a certain application prospect of large triaxial tests of field rock body samples or physical simulation test samples in the fields of mechanics, tunnels, bridges, metros and the like.