The vertical distance between the vibration source and the sensing channel is one of the important indicators concerned by the operators of optical cables and cables. It has important guiding significance for the safe disposal of the transmission line. A calculation method of the vertical distance between the vibration source and the sensing channel based on distributed vibration monitoring system(DVS) is proposed. Through real-time acquisition of cable signal data, the attenuation characteristics of vibration wave are analyzed, the appropriate calculation model of vibration wave amplitude spectrum is selected, and the distribution equation of the amplitude spectrum and the distance between the vibration source and the vertical distance is given, as well as the approximate calculation method of the vertical distance. Experiments show that the vertical distance error calculated by this algorithm is small, which meets the engineering design requirements and has high practical application value.