The red phosphor Ca3Y2Si3O12:Eu3 was synthesized by the high temperature solid-state method. The Eu3 ion doping concentration, flux and Gd3 co-doping on the luminescence properties were studied. XRD analysis showed that the principal crystalline phase was Ca3Y2Si3O12, attributed to monoclinic system. Fluorescence spectroscopy showed that the emission spectrum of silicate phosphor Ca3Y2Si3O12:Eu3 consisted of two main emission peaks, located at 590nm(5D0 → 7F1) and 614nm(5D0 → 7F2). Monitored with the strongest peak of 614nm, excitation spectrum was obtained which ranged from 200 to 500nm. The results showed that the emission intensity of the phosphors firstly increased and then decreased with the increasing of the doping concentration of Eu3 ion. It is found that the optimum doping concentration of Eu3 ion was 20mol%. The influence of several kinds of fluxes was discussed that The influence of several kinds of fluxes was discussed that the phosphor emission intensity decreased by adding a certain amount H3BO3, but increased significantly by adding NH4F. There is little effect to the phosphor emission intensity by adding NaCl or CaF2. Gd3 ion could be acted as a good co-activator, improving the emission intensity of Eu3 ion.