Macrostructure and microstructure of TiAl alloys in two kinds permanent mould casting and in ceramic mould casting were observed by OM（optical microscope） and SEM（scanning electron microscope） . The results show that gain size on fine gain layer of surface of TiAl alloy plate in permanent mould is decreased greatly

and width of columnar grain zone is narrowed

meanwhile

volumetric fraction of equiaxed grain in the center is decreased sharply with the decrease of grain size. Fine grain on surface of TiAl alloy plate in permanent mould castings is composed of random oriented lamellar colony

and columnar grain consists of oriented lamellar structure whose direction is perpendicular to the growth direction. Equiaxed grain in the center is composed of random oriented lamellar structure with obvious narrow lamellar spacing.