Abstract: Plate-like α-Alumina（α-Al<SUB>2</SUB>O<SUB>3 </SUB>）particles were synthesized by using 5% （mass fraction）α-Al<SUB>2</SUB>O<SUB>3</SUB> as seed crystal adding and with NaCl-KCl as molton salt.Influence of starting materials and calcination temperatures on the phase composition and morphology of α-Al<SUB>2</SUB>O<SUB>3</SUB>&nbsp; particles was studied.Synthesized products were characterized by XRD,SEM,TEM,and BET.Formation mechanism of the products was also discussed.Results showed that when Al（OH）<SUB>3 </SUB>was used as starting material,synthesized product at 900 ℃ was mainly composed of α-Al<SUB>2</SUB>O<SUB>3</SUB>&nbsp; and&nbsp; κ -Al<SUB>2</SUB>O<SUB>3</SUB>,and most synthesized particles showed alveolate morphology.At 1 100 ℃,single-phase α-Al<SUB>2</SUB>O<SUB>3</SUB>&nbsp; was developed,but most of the plate-like particles were aggregated.In contrast,using porous amorphous Al<SUB>2</SUB>O<SUB>3</SUB>&nbsp; as starting material,well-developed plate-like α-Al<SUB>2</SUB>O<SUB>3</SUB>&nbsp; with uniform size were obtained just at 900 ℃.