In this paper, the effects of Al electrode thickness, interdigital duty ratio, reflector grating period and topology on insertion loss, out-of-band rejection and rectangle are investigated with a single layer and ladder structures based on 128 YX-LiNbO3 materials, In order to reduce the passband ripple and insertion loss, an interdigital transducer (IDT) reflector grating structure is designed, which can reduce the in-band peak loss of the resonator before and after optimization by 8, 84% and 0, 55%, respectively, Finally, a low interpolation loss high frequency surface acoustic wave (SAW) filter is designed based on this reflector grating structure, The results of the finite element simulation show that the center frequency of the filter is 2, 520 5 GHz, the insertion loss is -0, 502 12 dB, the out-of-band rejection is greater than 30 dB, and the -3 dB loss bandwidth is greater than 98 MHz,