The Lamb waves and horizontal shear waves' propagation in LiTaO3 thin plate is investigated as a function of Euler angles. Both velocity and electromechanical coupling factor largely depend on the plate's thickness. Around (0°, 30°, 0°), LiTaO3 thin plate has a high velocity and a suitable coupling factor for a high frequency filter. Authors fabricated A1 mode Lamb wave resonators in (0°, 39°, 0°) LiTaO3's thin plate. Lamb waves' velocities and leaky Lamb wave' velocities were measured by network analyzer and ultrasonic microscopy. Measured velocities correspond to the ones calculated by FEM. Velocities higher than 20,000 m/s were obtained. It is then shown that A1 mode Lamb wave close to (0°, 30°, 0°) LiTaO3 thin plate is suitable for high frequency devices.