A new chemical precipitation method for silica encapsulation was firstly used in surface treatment of SrAl2O4:Eu2+, Dy3+ phosphors. X-ray fluorescent spectrometer (XRF), FTIR and scanning electron microscopy (SEM) results showed that a dense layer of silica is formed on phosphor surface after being encapsulated for 2.5 h under the condition of pH 10.5 and T= 80 +/- 1.0 degrees C. Water-resistance and photoluminescence measurement results showed that encapsulation amount and dispersing media play an important role in water-resistance of phosphors. Using glycol as dispersing media and controlling encapsulation amount at 5 wt.% would effectively improve water-resistance of SrAl2O4:Eu2+, Dy3+ phosphors at the cost of a minor loss of persistent phosphorescence. (c) 2005 Published by Elsevier B.V.