The invention discloses a rapid detection device and a detection method for track plate deformation. The device comprises a beam, a support sleeve, a telescopic leg, a tension spring, a fixing bolt, abracket, and a PSD laser system, wherein the telescopic leg is located in the support sleeve, and the lower end of the telescopic leg is exposed outside the support sleeve; the upper end of the support sleeve is fixedly connected with the lower end surface of the beam through the fixing bolt; the tension spring is arranged between the beam and the upper end of the telescopic leg; the upper end ofthe beam is provided with the bracket; the bracket is provided with the PSD laser system; the PSD laser system is wirelessly connected with a detection system. Compared with the prior art, the rapiddetection device and the detection method for the track plate deformation have the advantages that deformation detection is performed on a CRTS III type track plate, the accuracy is improved and the requirements on the field environment, personnel and equipment are reduced compared with the conventional on-site detection; the measurement method is rapider, more accurate and more cost effective than the existing measurement method.