Abstract: Propagation of nonlinear waves in a fluid-filled thinelastic foundation is studied in this paper. The material of the tube isassumed to be linear elastic, the reaction of foundation is calculatedbased on Winkler model, and the fluid is incompressible and inviscid.Initially, the tube subjected to a uniform inner pressure P_0 is in astate of static equilibrium. The dynamic displacement field and thevariations of inner pressure and fluid velocity are considered as adisturbance superimposed on this static deformation. The nonlinearequations of motion are obtained by considering the massconservation and the balance of linear momentum. With the reductiveperturbation method, the KdV equation is derived in the longwaveapproximation. It is shown that the system can have a solitary wave solution.