Abstract: A series of trivalent europium ions(Eu3+) and alkali metal ions(Li+,Na+,K+) coactivated molybdate phosphor AMoO4 (A=Ca,Sr) was fabricated by solid-state reaction, which could be used as supplementary lighting material for white light emitting diodes (LEDs). X-ray diffraction (XRD) patterns show that the lattice parameters decrease and the diffraction intensity remarkably increase when Eu3+ and Na+ ions are doped into the phosphor. The excitation and emission spectra of samples are investigated. The excitation spectra cover the region from 240nm to 500nm and have an excitation peak at 470nm, which indicate that this phosphor can be excited effectively by the emission of GaN-based LED; the emission spectra show the samples can emit red light whose peaks are located at 616nm and 624nm. The influence of alkali metal ions dosage ( molar fraction) on the luminescent properties of AMoO4: Eu3+ is investigated and the results indicate that 0.25 is the appropriated dosage. The reactive time and temperature have obvious effect on the luminescent properties. The luminescent intensity will reach the maximum when it was sintered at 800℃ for 3h.