The invention discloses a structure for detecting a disengaging status of a ballast-less track base of a high speed railway by impact elastic waves, wherein one side of the top surface of the ballast-less track base is uniformly provided with multiple elastic wave detection points along a route direction, and the side of each elastic wave detection point is respectively provided with an impact elastic wave trigger point; the structure further comprises a computer, a data acquisition unit, an acceleration sensor for detecting the elastic waves on each elastic wave detection point, and an impact elastic wave trigger device for triggering the impact elastic waves on each impact elastic wave trigger point; the signal output end of the acceleration sensor is connected with the signal input end of the computer through the data acquisition unit. The structure can overcome the disadvantage that the resolution ratio of the geological radar cannot meet the millimeter disengaging requirement, and the disengaging status of the ballast-less track base can be precisely and effectively evaluated by analyzing the spectrum characteristics of the impact elastic waves.