Tantalum silicide films are prepared from a composite $TaSi_{28}$ target source and subjected to rapid thermal annealing($500-1100^{circ}C$, 20sec) in Ar ambient. The formation and the properties of tantalum silicides have been investigated by using 4-point probe, x-ray diffraction, scanning electron microscope(SEM), Auger electron spectroscope(AES), and ${alpha}$-step. It has been found that the sample annealed above $700^{circ}C$ forms a polycrystalline $TaSi_2$ phase, and grains grow in granular form regardless of the kind of substrates. The mechanism of the formation of tantalum silicide is the nucleation and growth by Ta-Si short range reaction. The tantalum silicide film has the relatively low resistivity($70-72.5{mu}{Omega}-cm$) and smooth surface roughness.