The invention provides an apparatus of carrying out a stress relieving measurement method and carrying out a simulation test in a rock cavern and a method thereof. The apparatus comprises a test cavern, a test stand arranged in the test cavern, a test material arranged on the test stand, a three-dimensional prestress loading device used for loading the test material, a drilling machine and accessory equipment used for relieving a test, a stress test component buried in the test material and a test apparatus connected to the stress test component. Fixation and prestress loading are performed on the test material. The drilling machine and accessory equipment drill a hole in the test material and then a test component is buried in the hole. The prestress loading device comprises a preposition force transmission plate arranged on a front end surface of the test material, a counter-force column which is arranged between an upper portion cavern wall and the test stand in a supported mode, a force transmission component arranged on each end surface of the test material, and a pressurization and support component. In the invention, simulation testing can be performed on a single test method, quantification description is performed on test precision of the equipment, or test precision comparison among different methods is performed.