New color centers in Eu2+:Sr9Ca(PO4)6Cl2 are reported in this paper, their absorption bands are Peaking at 708, 785, 845 and 990 nm respectively. The photootimulated luminescence by stimulation into those bands are the same as that by stimulation into F bands. Through comparison with the centers in other crystals, we may assign those new bands to F aggregates, i. e. FA centers. The shift between the stimulation bands of FA centers and emission band of Eu2+ is greater than that between F bands and emission band of Eu2+, so the FA centers are more efficient for the application of this PSL phosphor.