In the present paper, the electroluminescence emission from a doped polymer layer was studied. The blue fluorene PFO was used as the host material and MEH-PPV as the dopant. The spectral characteristics and color stability of the emission on CIE chromaticity diagram were investigated. With the doping ratio of 2.5 Wt%, the device shows turn-on voltage of 3 V, and color coordinates of (0.33, 0.33) at 11 V. The color coordinates of the device was stable with changing voltage in a large range, and located in the ideal white area in the range of 5~20 V voltage.