Abstract: Objective: Partial uneven waves in the track have a significant impact on the vibration of high\|speed railway vehicle systems. From the perspective of track structure vibration control, it is necessary to study the distribution characteristics and effect factors of unevenness\|sensitive wavelengths in ballastless tracks in order to reduce track vibration and extend the lifespan of track structures. Method: The dynamic algorithm of the vehicle\|CRTS\|Ⅱ slab track coupling system is introduced, and the motion equations of this system are listed. The wavelength of track irregularity sensitivity is obtained through calculation. Based on the analysis of the distribution characteristics of the CRTS\|Ⅱ slab track sensitivity wavelength, four influencing factors including train operating speed, fastener, CA (cement asphalt) mortar, and subgrade are selected. The calculation parameters for different operating conditions of each influencing factor are chosen to analyze the impact of different parameter values of each influencing factor on the track irregularity sensitivity wavelength. Result &Conclusion: The sensitive wavelengths of track irregularities generally increase with the increase of train speed, but not strictly monotonic changes. The parameters of fasteners mainly affect the sensitive wavelengths of low order (first 5 orders), and compared with the vertical damping of fasteners, the effect of vertical stiffness of fasteners on sensitive wavelengths is greater. The parameters of CA mortar have almost no effect on sensitive wavelengths of track irregularities. The influence of parameters of subgrade on sensitive wavelengths of track irregularities is similar to that of fasteners.