A Ho-doped silica fiber with a high verdet constant is prepared by a modified chemical vapor deposition (MCVD) method. The phenomenon of the Faraday effect enhancement of a Ho-doped silica fiber is theoretically analyzed by the wave transition contribution analysis method based on the wave-particle duality of light. The Verdet constant of Ho-doped silica fiber is calculated with the wavelength range from 1310 nm to 1550 nm. Through experimental measurement, it is found that the Verdet constant of the Ho-doped silica fiber has a wavelength dependency. The experimental results show that the Verdet constant values of the Ho-doped silica fiber at 1310 nm and 1550 nm are 4.5 times and 1.6 times that of the conventional single-mode silica fiber, respectively.