Displacement monitoring device and use method thereof for three-dimensional similar simulation material simulation test

The invention discloses a displacement monitoring device and a use method thereof for a three-dimensional similar simulation material simulation test. The displacement monitoring device is mainly structurally characterized in that a micro-pressure sensing device is provided with a liquid storage cavity structure, directly buried inside a similar simulation material and respectively connected with a liquid storage box, an acquisition instrument and a computer, and complicated internal local displacement monitoring of a similar simulation material is ingeniously converted into simple pressure signal detection and output, so that the displacement monitoring device is simple and reasonable in structure, real and accurate in test result and small in system error, has automatic reading and full reading functions, and effectively solves the technical problems that 'change points' cannot be monitored, only overlaying rock sinking can be monitored, overlaying rock lifting cannot be monitored, and consequently, simulation test results are incomplete, untruth and inaccurate in the prior art.