The Ca(MoxW1-x)O-4: Eu3+ phosphors with different concentrations were prepared by a precipitation process. The crystal structure was confirmed to be body centered tetragonal scheelite by X-ray diffraction measurement, and the morphology was characterized by field emission scanning electron microscopy. The photoluminescence measurement, including emission spectra, excitation spectra and fluorescence decay curves, were carried out. The results indicate that the best Mo:W ratio is 6:4, since the integral intensity of Eu3+ red emission (616 nm) in Ca(MoxW1-x)O-4: Eu3+ phosphors increases nearly 100% and 65% compared with the intensities in CaMoO4: Eu3+ and CaWO4: Eu3+. In this work, the best doping concentration is confirmed to be 25 mol% in Ca (Mo0.6W0.4)O-4: Eu3+ phosphors. Exchange interaction was confirmed to dominate concentration quenching of Eu3+. Auzel's model was used to explain the self-generated quenching process of Eu3+ and obtain intrinsic lifetime of D-5(0) level. Furthermore, a new method was proposed for calculating the refractive index.