A method both convenience for generation and calculation for anticipated ASE waveform in spun fiber Raman amplifier,by analyzing the NLSE of signal and pump wave in fiber,is proposed.According to its time domain characters,a non-Gaussian noise ASE model is established and the term is added to the NLSE simultaneously by considering birefringence rotation effect in spun fiber Raman amplifier.By solving the equation with Split Step Fourier Method,ASE in spun fiber Raman amplifier is investigated.Numerical results for the ASE noise power spectrum are validated.