Abstract: Starting from the equations of motion for small dynamic fields superposed on a bias, helped with the perturbation theory, the model relating the velocity shifts of SAW (Surface Acoustic Wave) to temperature and stress is deduced and six independent sensitive coefficients relating the six tensor components of stress are then defined. The temperature and stress sensitivity of La₃Ga₅SiO₁₄ in double rotated plane are investigated. The calculated results are presented with the aid of contour plots. Combining with the electromechanical coupling and power flow angle characteristics, some optimal propagation and cut directions of SAW substrate with potential application values for frequency control or sensor are put forward. And to the substrate defined by Euler angle (0,150°,22°), the temperature and stress sensitive characteristics are investigated through experimentation. The validity of the calculation methods and results in this paper are tested by the comparison between theoretical results and experimental ones for both quartz and La₃Ga₅SiO₁₄.