We propose that nanomaterials are used for fibers. A novel nano-InP doped fiber has been fabricated by the method of modified chemical vapor deposition (MCVD).It has been measured that the doping concentration of phosphorus element is 0.1%. The relationship between refractive index and the wavelength is obtained by fitting experimental data to Sellmeier equation. Dispersion of the fiber has been calculated in the wavelength range of 1.2-1.6 μm. As the wavelength varies from 1.20 μm to 1.60 μm, dispersion parameter D increases but is always negative. It has been found that the dispersion of nano-InP doped fibers is strongly changed compared with standard single-mode fibers, due to the nano-InP dopant which leads to a higher refractive index difference.