The surface material for fabricating conventional SAW wafer is Al,which is oxidized in air,and it is easy to form a dense aluminum oxide(Al2O3) film.Due to the difference of etching rate among the aluminum oxide (Al2O3) film,Al and the substrate piezoelectric material,it results in complexity of the ion beam trimming process. An ion beam trimming method for SAW devices is introduced in this paper. By using this method,the target frequency of SAW devices can be adjusted up and down,and the frequency concentration can be further improved, so that the process problem that it is difficult to improve the frequency accuracy of lowfrequency narrowband SAW devices and SAW highfrequency devices above 2 GHz is solved.