A high frequency SAW device and the substrate thereof are disclosed. The disclosed high frequency SAW device does not need to use the conventional and expensive sapphire substrate as its substrate. Besides, the disclosed substrate for a high-frequency SAW device can replace the conventional sapphire substrate in the use of the substrate for a high frequency SAW device. The disclosed high frequency SAW device comprises: a substrate; a first buffering layer forming on the surface of the substrate; a second buffering layer forming on the surface of the first buffering layer; a piezoelectric layer forming on the surface of the second buffering layer; an input transformation unit; and an output transformation unit, wherein the input transformation unit and the output transformation unit are formed in pairs on the surface of or beneath the piezoelectric layer.