Eu3+ doped La3PO7 phosphors were synthesized by co-precipitation method. The crystal structure and optical properties of the as-synthesized samples were investigated by XRD, SEM, FT-IR and FL. The influences of pH and doping content of the as-prepared samples were also discussed. The results show that the single-phase La3PO7:Eu3+crystals with monoclinic structure can be obtained. The photoluminescence spectra show strong red emission at 617 nm originating from 5D0-7F2 transition of Eu3+ ions under 280 nm light excitation. The concentration quenching phenomenon is observed when the doping content is over 4% (mole fraction),and the concentration quenching mechanism is caused by the exchange interaction of Eu3+ ions.