Abstract: In allusion to the influence of internal solitary wave on the low-frequency sound propagation in threedimensional shallow sea,the influence rules of internal wave on the propagation characteristics of low-frequency acoustic signal are simulated and analyzed in a study of sound energy flux,which is based on the finite element method of three-dimensional low-frequency sound field in shallow sea under Oxyz coordinate system.The result shows that,under the influence of internal wave,in the xOz plane,the deflection angle of the acoustic energy flux's vertical component follows a periodic fluctuation rule,when the acoustic source depth increasing,the influence depth of internal wave on the deflection angle also increases.In the xOy plane,when the source is above the thermo cline,the deflection angle of the acoustic energy flux's horizontal component would be wider with the increasing of receiving depth,and the influence of internal wave on acoustic energy flux would be weakens with the increasing of source depth.