Abstract: The co-precipitation methods with CO（NH₂）₂ as starting material of preparing rare earth doped YAG phosphors for transparent ceramics was studied. The structure and morphology of the powder were investigated by DTA-TG, XRD, SEM and IR spectrum. The results indicate that the mass loss value is about 40% after calcining at 1200℃. And well-crystallized YAG powder is obtained with particle size in the range of 150-200nm. The SEM of the fracture surface of the sintered body shows that the grain size is about 1-2μm and the pore volume is very low. The ceramics body of high optical property is obtained after sintering at 1750℃,with the transmittance of about 75%.