Abstract: A model evaluating the signal loss of the acoustic beam of double transmissions from random rough surfaces was established based on the riesnel approximation and phasescreen approximation.A simple analytical solution was achieved using the exponential substitution approach to remove the nonlinear integral term.The factors that affect the signal of double transmissions from random rough surfaces was analyzed.The research results demonstrate that the signal loss is not only related to root-mean-squire height,but also related to the distance of wave traveled in the materials.