Hetero acoustic impedance interface was engineered in the LNOI technology to form a low-loss waveguide using solidly mounted thin-films. This unique waveguide structure can not only confine the acoustic energy within the piezoelectric layer but also significantly suppress the unwanted substrate energy radiation loss. Therefore, a universal performance improvement on resonators, wide band filters and low loss acoustic delay lines can be achieved. The performance indexes of the novel surface acoustic device in LNOI technology is typically 5~10 times better than conventional SAW devices and 2~3 times better than commercial AlN bulk acoustic wave (BAW) devices, consolidating the huge potential for LNOI in next generation RF acoustic devices.