The wide range for power dependence of phase shift spectrum of stimulated Brillouin scattering (SBS) is characterized through mathematical modeling and simulation; a phase shift measurement system of SBS loss based on heterodyne pump-Stokes technique is designed. The phase shift spectrum of 400 m standard single-mode fiber in SBS loss is measured in a pump wave power range of 5 μW~15 mW and a Stokes wave power range of 3.5~110 mW. The mechanism of measured center-asymmetric phase shift spectrum in SBS loss is analyzed. The results indicate that phase shift range of SBS loss has a good linear relationship with Stokes wave power and is almost independent of pump wave power. The measured center-asymmetric phase shift spectrum of SBS loss is mainly caused by fiber dispersion and nonlinear effect induced by nonlinear refractive index. According to the theoretical and experimental results, the applications of power dependence of SBS phase shift spectrum in microwave photonic signal processing and distributed optic-fiber sensing are analyzed, which provides theoretical basis for the design of application systems based on SBS phase shift.