Novel luminescence ultrafine fiber mats containing K-11[Eu(PW11O39)(2)] [EuPW11] and Na-9[EuW10O36] [EuW10] entrapped in polyvinyl alcohol (PVA) have been successfully prepared by electrospinning method. By comparing the luminescence emission spectra of EuPW11/PVA and EuW10/PVA Ultrafine fiber mats, we conclude lower site symmetry of Eu3+ in the EuPW11/PVA ultrafine fiber mats. We further investigate the different configurations of EuPW11 and EuW10, which lead to the different site symmetry of Eu3+ in the ultrafine fiber inats of EuPW11/PVA and EuW10/PVA. Fluorescence property shows EuPW11/PVA Ultrafine fiber mats display pure red emission. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 1369-1374, 2009