The high loss of polymer optical fiber (POF) is a great obstacle to replace silica glass fiber in local area nets.In o rder to overcome this problem,a novel quantum dot (QD) doped polymer fiber ampli fier (QDPFA) is presented in this paper.In the QDPFA,CdSe/ZnS QD is used as the gain medium.Based on a two-level rate equation and the pump power propagation equation,the gain performance of the CdSe/ZnS quantum dot doped polymer fiber am plifier is calculated.The rate and power propagation equations of the model are further solved to investigate the effects of the CdSe/ZnS QD doped concentration ,QD doped polymer fiber length,signal and pump intensities on the gain spectra.T he results show that when pumped in the milliwatt level,the gain can be more tha n 35dB.The needed pumped power to get the same gain is just about 1/10000of t hat in the usual dye-doped polymer fiber amplifier.The corresponding relation b etween the pump power and QD doped concentration is shown and the best number is about 6．33×10⁷/mW.QDPFA has wide room-temperature gain spectra in the range of 550－610nm,which covers the low-loss window of PMMA POF.