Nanoscaled SrAl12O19:Er3+ and SrAl12O19:Yb3+, Er3+ phosphors were synthesized by a combustion method. The emission intensities of every sample were compared by a new method with the emission of codoped Gd3+ ions as a reference. Compared with their bulk material prepared by the solid-state reaction method, a higher Er3+ quenching concentration, as high as 20%, was observed in the nanoscaled phosphors for both visible (VIS) and near infrared (NIR) emissions. The higher quenching concentration in both VIS and NIR regions for nanoscaled samples are related to the structure characteristics of the nano particles. The influence of the introduction of Yb3+ ions on the emission spectra intensity was also investigated and discussed.