Although the refractive index of the dye solutions is lower than that of the cell material, the reflectivity is high as the light beam grazes at the inner surface of the cell and the solution is of high gain, a number of low order leaky modes can be supported by the leaky waves. Furthemore, the influence of the pump light and the laser beam on the dye solution will bring about the nonuniform distribution of the refractive index of the solution, so the solution can be self-guided. Our experiments and the photos have proved the above analysis.