Stimulated Raman scattering (SRS) is an important frequency-conversion technique that can substantially extend the spectral coverage of the solid lasers. By contrast to inorganic crystals, many organic crystals possess Raman scattering over 3000 cm^-1. Therefore, large wavelength conversion can be realized just by one-order Raman shift. Using fast solution growth method, we grow single-crystalline microfibers of tetraphenylphosphonium bromide (TPPB）, the length-to-diameter ratio of which is up to 10⁴:1. TPPB single-crystal microfibers exhibit an excellent optical wave-guiding property and multiple-color SRS generation under a continuous-wave pump at 532 nm. And the SRS generation threshold is showed to be less than 0.7 mW, which benefits to the strong optical confinement property of the single-crystalline fiber. The TPPB single-crystal microfiber developed here may find practical use in miniature optical frequency devices such as compact Raman lasers to provide varied laser wavelengths for applications in imaging, spectroscopy or optical communications.