Abstract: A range dependent tomography method is proposed to obtain the range dependent Sound Speed Profile(SSP).A segmented matched-field inversion method based on Empirical Orthogonal Functions(EOFs)is used to invert the equivalent average SSP.The SSPs of segment points are calculated by an iterative method and the horizontal distribution of the SSP is obtained.Both numerical simulation and experimental acoustic data from the South China Sea use to validate the proposed method.The results demonstrate that the range dependent SSP can be obtained correctly with the Root Mean Square Error(RMSE)of 0.8 m/s.The inverted SSPs are consistent with the expendable bathythermograph(XBT)measurements at each site.The range dependent tomography method is meaningful for mesoscale structure inversion and sonar application.