In order to study the influence of Stimulated Raman Scattering (SRS) on the gain performance of Fiber-Optic Parametric Amplifier (FOPA) based on Four-Wave Mixing (FWM),in this paper,the fourth-order Runge-Kutta method is used to solve the steady-state nonlinear coupled wave equation under the combined action of SRS and FWM.The influence of SRS on FOPA gain performance is analyzed in terms of pump interval,pump power,nonlinear coefficient,pump center wavelength,zero dispersion wavelength and dispersion slope.The research results show that when the fiber nonlinear coefficient γ≤2.5km-1·W -1,SRS will lower the gain of FOPA,that is,SRS has a negative effect on signal amplification； when γ>2.5km-1·W -1,SRS makes the FOPA gain spectrum flatter,which means SRS plays an active role in signal amplification.