The soliton self-frequency shift in a single-mode optical fiber has been studied by numerical simulation and experiment, with emphasis on the influences of various parameters of optical fiber and soliton pulse on it. Firstly, with split-step Fourier method for numerical simulation, it has been found that the soliton self-frequency shift increases with the increase of soliton peak power and nonlinear coefficient of the transmission fiber, and decreases with the increase of soliton pulse width and group velocity dispersion. Secondly, the soliton self-frequency shift effect in a 2-km-long single-mode fiber has been experimentally studied. By adjusting the peak power of the soliton, continuously tunable self-frequency shift with central wavelength from 5.44 nm to 26.64 nm has been achieved. The experimental results are consistent with the numerical simulation results. It has been shown that by flexibly adjusting the parameters of soliton pulse and optical fiber, the soliton self-frequency shift can be effectively tuned, which provides guidance for many practical applications of soliton self-frequency shift in optical fibers.