Abstract: A new ray-tracing method - total iterative ray-tracing method in random interface is studied. First, it starts from the fact that the ray-path satisfies the Fermat principle in the total ray-path, adjustment is obtained by a positive tridiagonal matrix equation which is reduced from one-order Taylor expansion. Further, total iterative ray-tracing is realized. When the adjustments on the total ray-path satisfy the preset precision, the procedure of the ray-tracing is completed. Numerical tests based on this method show that this algorithm is fast in the random interface velocity distribution and the results are accurate enough. At the mean time, travel time can be given in the procedure of ray-tracing. It offers a new efficient ray-tracing method for seismic tomography.