The article presents the continuous and discrete dynamic models of a thin-walled curved pipe. On the basis of semi-momentless theory of anisotropic laminated shells and Lagrange’s equation of the second type a coupled system of resolving equations has been deduced. A comparative estimate of the results has been carried out. The article shows that the results of the FEM calculations and those of the analytical solutions agree with each other. There has been analyzed the dependence of the lower natural modes and frequencies spectrum on the internal pressure, as well as on the geometrical, structural and technological factors. Some regularities have been discovered.