The gain spectrum of the neodymium-doped wideband fiber amplifier was modeled and simulated by Matlab, and the intelligent optimization algorithm (genetic algorithm) included in Matlab was used to optimize the fiber length and doping concentration to maximize the peak gain (find the optimal fiber length and doping concentration within the set range). According to the set signal optical wavelength range (1300 nm~1400 nm) and the corresponding neodymium ions four-level transition structure, the pump optical wavelength (800 nm) is designed and the four-level structure rate equation and power propagation equation are established, and Matlab programming calculates the change of gain with fiber length, neodymium ions doping concentration and pump optical power. According to the obtained gain curve, it can be inferred that under the parameter range set in this study, the gain of the neodymium-doped fiber amplifier increases significantly with fiber length and neodymium ions doping concentration, while the pump optical power has almost no effect on the gain value.