This paper describes the polarization effect mechanism and the vector model analysis of stimulated Brillouin scattering in Brillouin Optical Time Domain Analysis (BOTDA) distributed optical fiber sensing system. Based on current research development, we analyze the polarization-dependent Brillouin gain spectrum, and introduce the control of polarization state and the suppression of polarization fading technology in the stimulated Brillouin scattering effect. Among them, Brillouin fiber sensing system vector modeling analysis and polarization state control technology have a good research prospect. Our analysis has certain reference value in the aspects of using the sensitivity of the polarization state to measure the temperature, strain and vibration information of the distributed sensing fiber and the aspect of suppressing the polarization fading to improve the spatial resolution of the fiber sensing system.