By adding CdSe/ZnS (core/shell) quantum dots (QDs) into polymethylmethacrylate (PMMA), (CdSe/ZnS)/PMMA QDs doped fiber material is prepared. The absorption-emission spectra and the refractive index of (CdSe/ZnS)/PMMA are measured in respect of doping concentrations. Comparing with the case of the QDs dissolved in n-hexane, the absorption-emission peak wavelengths of the (CdSe/ZnS)/QDs are identical with PMMA substrate. In the doping concentration range 0.013~0.130 mg·mL-1, the observed photoluminescence (PL) peak intensity shows a single peak and follows an exponential square law. As the doping concentration increases, the refractive index increases by 0.0013 at room temperature, and the PL peak wavelength appears a red shift. The maximum red shift is limited by Stokes shift, likely to be related with re-absorption/excitation effect and concentration effect of QDs.