The cosmological perturbations on a bouncing brane are studied . The brane is moving inside a Klebanov-Strassler throat where the infra-red region of the geometry is smoothly cut off . For an observer confined to the world-volume of the brane , this results in a non-singular bouncing mirage cosmology . We have calculated the scalar perturbations corresponding to the normal displacements of the brane . This is performed in the probe brane limit where the gravitational back-reaction of the brane on the bulk throat is absent . Our model provides a framework for studying the transfer of fluctuations from a contracting to an expanding phase . We find that the spectral index of the dominant mode of the metric fluctuation is un-changed , unlike what is obtained by gluing contracting to expanding Einstein universes with the help of the usual matching conditions . Assuming that the fluctuations start off in a vacuum state on sub-Hubble scales during the contracting phase , it is shown that the resulting spectral index n _ { s } on super-Hubble scales in the expanding phase has a large blue tilt . When the brane is moving slowly inside the throat and its kinetic energy is negligible compared to its rest mass , one finds n _ { s } = 3 . For a fast-rolling brane with a large kinetic energy , the spectral index is n _ { s } = 2.3 . This may put severe constraints on models of mirage cosmology . Keywords : D-brane , Bouncing cosmology