A PbSe quantum-dot-doped fiber amplifier (QDFA) is realized. Using PbSe quantum dots as the gain media doped in the fiber, the broadband signal light ranging from 1250 nm to 1370 nm is amplified in an all-optical framework，which consists of the quantum- dot- doped fiber, 980 nm pumping laser, wavelength division multiplexing, and isolator. For the diameter of 50 mm quantum-dot-doped fiber, there is evidence to show that the excitation threshold is 62 mW, the bandwidth is 120 nm at -3 dB, the flattened bandwidth is 90 nm at -1 dB, and the signal gain is up to 12 dB. The wide bandwidth, flattened gain, and low noise of QDFA are advantageous over the traditional erbium doped fiber amplifiers. The QDFA presented in this paper provides a new solving way of the growing demand for the bandwidth of fiber amplifiers in the current dense wavelength division multiplexing(DWDM) system.