Abstract: Yellow phosphor Y₃Al₅O₁₂:Ce is synthesized by solid-state reaction technology. This paper studies the influences of flux on the luminescent properties of YAG:Ce phosphor. The XRD spectra tests show that the flux is beneficial to crystallize the phosphor with no other phases formed except the cubic. The mixture use of H 3BO4 and SBL is better than using single flux. The adding of the flux increases the excitation of phosphor and the strength of emission spectra of YAG:Ce. The particle size is also effectively decreased.