Fiber optic amplifier is an important component of fiber optic communication and the use of the properties of rare earth ions to dope the fiber core is an important way to obtain greater amplification and reduce loss. Because of the unique light-emitting properties of Bismuth ions, the Bismuth doped fiber amplifier (PDFA) has a wide range of applications in the field of fiber amplifier. This paper focuses on the spectral analysis of Bismuth-doped ( ) fiber amplifiers under different parameters by referring to the absorption spectrum of . And the energy level structure of was selected for a wide range of amplification windows → pumping scheme corresponding to the pumping wavelength of 950 nm, and the rate propagation equation and power transmission equation were established based on the previous work. The numerical simulations were also carried out by MATLAB programming. The effects of doping concentration, fiber length, and pump power on gain, noise index, and output power were analyzed and summarized by MATLAB plotting. In the future, researchers can use neural network algorithms to obtain the combination of Bismuth-doped fiber amplifier parameters that will achieve maximum gain, thus enabling advances in information transmission rates and distances in real-world communications.