Amplified spontaneous emission (ASE) is one key factor influencing the performance of high-peak-power high-energy pulsed fiber amplifiers with low repetition rate. The main methods used for ASE suppression in pulsed fiber amplifiers, including filtering, optimization of pump characteristics (pump power, backward pumping, and pumping schemes), and optimization of seed characteristics (signal power and signal pulse width) are reviewed. The suppression effect comparison among the above methods indicates that, filtering and synchronous pulse pumping are major technical means to suppress ASE and to achieve high-peak-power high-energy pulse outputs.