The wavelength variation of a laser-dye-type random laser is observed experimentally.It is found that the emitting wavelength of a random laser changes with the change of concentration of the gain material Also,the actual radiation wavelength is influenced by the pumping rate of the source,the cavity competition and the concentration of scatterers.Since the pioneering work of Ambartsumyan et al.,[1,2] random lasers have attracted much attention both theoretically and experimentally owing to their potential applications.Many systems have shown lasing behavior,such as neodymium-glass powders,[3]dye-TiO2 solutions,[4] nanoclusters of ZnO,[5] conjugated polymer films,[6] dye infiltrated opals,[7] dyeTiO2 polymer films,[8] and laser dye within liquid crystals.[9]