Abstract: Langatate (LGT) is a novel piezoelectric crystal, whose structure is similar to that of quartz. The numerical analysis of the propagating characteristics of surface acoustic waves (SAW) on LGT and quartz are presented. The results show that the phase velocity of SAW on LGT is generally about 1000 m/s slower than that on quartz. Like the quartz, there are cuts with zero temperature coefficient and pure module orientations on LGT. Compared with quartz, LGT is with larger electro-mechanical coupling constant (K²). Based on present material constants reported so far, the characteristics of SAW on LGT with different material constants are also calculated. The results show that there are distinct deviations with different material constants, especially the temperature coefficient of frequency (TCF).