The invention discloses a damage detection method for the thickness of a floor slab, which comprises a transparent glass cylinder and a floor slab, the transparent glass cylinder has a detection rod plugged into the inside of the transparent glass cylinder, and a sliding sliding rod is sleeved on the outside of the transparent glass cylinder. shaft, the outer surface of the sliding shaft is fixedly connected with an upper positioning rod, one side of the sliding shaft is provided with a fixing bolt, and the bottom end of the detection rod is fixedly connected with a bottom shaft. The damage detection method for the thickness of the floor slab improves the measurement of the damage method measuring device for detecting the thickness of the floor slab more accurately, is convenient to use, simple to operate, saves time and effort, and the damage method measuring device for detecting the thickness of the floor slab only needs One-person operation can complete the measurement, which can improve the efficiency of measuring floor thickness by using the damage method and reduce personnel operations. It is convenient and efficient, and easy to carry. Compared with the previous two-person operation, it saves manpower and can avoid the unevenness of the formwork joints. error, the prior art is more accurate.