The yttrium aluminum garnet(YAG) ceramics are prepared by using the solid-phase sintering with YAG∶Ce 3+ phosphor powder as the raw material. In order to improve the sintering performances of YAG ceramics, the active SiO2 is coated on the YAG∶Ce 3+ phosphor powder surface by the sol-gel method and the CuO-TiO2 composite phase is added as sintering aids. The particle size, the optical performances before and after coating, and the micro-morphologies of the phosphor powder are analyzed and the mechanical properties and microstructures of YAG ceramics are investigated. The research results show that the particle size can be effectively reduced by grinding and ball-milling. The sintering and densification process of ceramics is promoted by the coating of the active SiO2. When the coating amount (mass fraction) is 2%, the sintering temperature of YAG ceramics is decreased to 1575 ℃, the relative density reaches 96.3%, the rock-well hardness is 87.6 HRA, and the fracture toughness is 1.8 MPa·m 1/2. Moreover, the sintering effect of the CuO-TiO2 composite sintering aids is superior to that of the CuO single sintering aids. When the mass fraction of CuO-TiO2 is 2% and the mass ratio between CuO and TiO2 is 1∶2, the sintering temperature of the YAG ceramics is reduced to 1450 ℃, the rock-well hardness is 88.5 HRA, the fracture toughness is 1.7 MPa·m 1/2.