Yb:S-FAP [Yb3+:Sr5(PO4)3F] have emerged as gain medium for high power laser systems with practical repetition rate.In the present manuscript Yb:S-FAP nano-powder was synthesized by co-precipitation method.The precipitate was then calcined at 600-1200oC to remove remained organism and impurities.The phases and morphologies of the powders were characterized by XRD,SEM and TEM.The results show that pure-phase hexagonal Sr5(PO4)3F powders were obtained with average aggregated size of 20-150 nm.The vibration peaks which related to OH in Yb:S-FAP crystal was not observed by FT-IR.The powders were sintered to dense at temperature of 1400-1600 ℃.