Abstract: The collapse behavior of Langmuir waves excited by laser near critical surface is numerically studied.On the basis of Zakharov equations in frame of strong turbulence,it is shown that Langmuir waves excited by transverse pumping plasmons near critical surface may collapse,leading to the formation of density cavity due to ponderomotive force.The interaction will lead to tendency of an equilibration of energy over both of transverse and Langmuir plasmons with the same frequencies near ωp,which is agreement with our numerical analysis.The value of width of the density cavity estimated is similar to the experimental result.