In this study, the effects of erbium-doped fiber amplifier (EDFA) on Brillouin and Rayleigh power spectrums are observed. For this analysis, Brillouin Optical Time Domain Analysis (BOTDA) configuration is used with an 18 km single mode fiber cable as the fiber under test (FUT) and 1550 nm band is utilized for the incident wave and EDFA. The scattered back wave is observed with both an RF spectrum analyzer and a high-resolution optical spectrum analyzer. The optical power level of Rayleigh backscattering did not change with respect to EDFA power; however, the SBS power level steadily increased. Compared to Rayleigh power, SBS becomes significant around and after the EDFA laser current of 270 mA.