Abstract: Co³⁺-doped LaBO₃ powders were synthesized by combustion method using La(NO₃)₃·6H₂O, Co(NO₃)₃·6H₂O), H₃BO₃, and C₂H₅NO₂ as the raw materials with the mole ratio of La(NO₃)₃·6H₂O+Co(NO₃)₃·6H₂O:H₃BO₃:C₂H₅NO₂=3:3:5. The synthesis process and crystal morphology of the target products La_(1−x)Co_xBO₃ (x=0.01~0.04) at 750~950 ℃ were studied. The influence of synthesis conditions on the crystal morphology of the powder products was analyzed. The optimal ratio of the raw materials, reaction temperature, reaction time, and doping dosage were obtained. In the results, the combustion synthesis method can be used to prepare the Co³⁺-doped LaBO₃ powders, and the experimental conditions are simple, the calcination temperature is low, the yield is high, and it is easy to industrialization. The optimal reaction condition is 900 ℃ and 4 h, the doping dosage of cobalt as modifier is x=0.03, and the products are La_0.97Co_0.03BO₃ powders. Under the optimal reaction condition, the products are the short rod-like powders in the uniform particle size distribution with the diameter of 115~185 nm and the length of 400~600 nm. The fluorescence excitation band appears at 330~440 nm for the Co³⁺-doped LaBO₃ powders, indicating that the Co³⁺-doped LaBO₃ powders with the uniform particle size and crystal morphology can be used as the substrate material for preparing the luminescent powders.