Soliton self-frequency shift (SSFS) is a phenomenon that Raman self-pumping continuously transfers energy from higher frequency components of optical pulse to its lower frequency components. It has been explored over the last decades, because it has many potential applications in the fields of all-optical wavelength conversion, ultra-fast all-optical switch, all-optical de-multiplexing and so on. In this paper, Firstly, using 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 width and group velocity dispersion. At the same time, third order dispersion is taken into account, which has a significant inhibitory effect on soliton selffrequency shift. Secondly, according to the existing conditions in the laboratory, self-frequency shift in a 2-km-long single-mode fiber has been experimentally studied, especially the influences of soliton peak power and optical fiber dispersion. A continuously tunable self-frequency shift with central wavelength from 4.29 nm to 43.25 nm has been achieved by adjusting the peak power of the soliton. It has been shown that the soliton self-frequency shift can be effectively tuned by flexibly adjusting the related parameters, which provides guidance for many practical applications of soliton self-frequency shift.