Abstract：From the actual measurement of the vibration wave induced from train with the geological condition of Karst collapse nearby railway，the vibration wave process and damping features of the wave are analyzed and discussed. The damping rule of vibration along railway is obtained and calculation is made for damping coefficient(0.2/m) in the hard plastic clay. From the distribution of damping coefficient，the safe depth of soil layer is presented for railway in given condition，which is about 7 meters. The damping coefficient may be impacted by precipitation，temperature，and the property of soil layer. In the research，the field measurement of vibration process from train is made，and the wave curve shows obviously a pulse feature in the process.
