To gain nanometer SrAl2O4:Eu,Dy phosphors, uniform fine precursors of Eu and Dy ion doping strontium aluminate were prepared by microemulsion technology. Using as-synthesized stuff, long afterglow phosphors SrAl2O4:Eu,Dy were obtained after sintered at 1200°C. TEM characterization showed the morphology of their grains is sphere-shaped with size less then 100nm. XRD analysis illuminated the crystal structure of SrAl2O4:Eu2+, Dy3+ phosphors is monoclinic. Fluorometry examination detected the peak in emitting spectrum is at 510nm, and at 310nm in exciting spectrum, which both have little blue shift contrasting to the same kind of phosphors synthesized by solid-state reaction method. Finally, the major parameters influencing the grain size of prepared phosphor powders were made a discussion.