Based on the characteristic of semiconductor quantum dots and evanescent wave fiber coupler, a novel fiber amplifier was proposed. This semiconductor quantum dots fiber amplifier (SQDFA) was fabricated by depositing PbS quantum dots prepared by solution route on the fused taper region. Optical amplification was realized by interaction between the signal evanescent field and pump's in the quantum dots. PbS quantum dots were synthesized by simply reverse micelle method. The size of PbS quantum dot was less than 10 nm measured by transmission electron microscope (TEM). The optical gain more than 4 dB was obtained at 1310 nm pumped by semiconductor-laser at 980 nm with 30 mW. The optical gain at 1310 nm shows the spectral blue shift resulted from quantum size effect. This compact quantum dots fiber amplifier has potential applications in high-speed broadband access network.