The invention relates to a detection device for wet-state compression deformation of an AGM separation plate. The detection device is characterized by comprising a frame body, a rotary shaft, a pressure meter, a thickness meter and a pressing block, wherein the pressure meter, the thickness meter and the pressing block are connected to form a whole body; the frame body comprises an upper bracket and a lower bracket; the rotary shaft is rotatably mounted on the upper bracket; the rotation of the rotary shaft drives the pressure meter, the thickness meter and the pressing block to move up and down relative to the lower bracket; the AGM separation plate is arranged into a clamp formed by the pressing block and the lower bracket; the detection device further comprises a diluted sulfuric acid groove; and the AGM separation plate is arranged in the diluted sulfuric acid groove. The detection device can be used for effectively detecting change conditions of a pressure value at a wet state and change conditions of a thickness value of the AGM separation plate.