According to the current vibration environment of airborne avionics and the trend of the full band noise reduction on phase noise,considering the electromechanical coupling characteristics of crystal system for noise reduction of the electromechanical synthetic optimization design under vibration is useful. A new method of physical characterization of crystal oscillator phase noise and deterioration characteristics under vibration is put forward for the first time from the working principle of the crystal. On this basis,the mathematical model is set up to optimize the phase noise at various operating conditions with the strength and quality of the constraints. The simulation calculation and experimental verification show that the proposed method can improve the phase noise level at the low frequency in the condition of phase noise at high frequency without deteriorating. The paper has achieved satisfactory results,and the scheme will be applied to engineering practice.