In the phase-sensitive electronic system, it requires steady phase against environment temperature and mechanical deformation to ensure the low distortion of signal. Phase characteristics of coaxial cable with different structures are theoretically analyzed and experimentally verified in the temperature range of -20-60 ℃ and static mechanical bending radius range of 50-200 mm, and the phase sensitivity change with temperature and mechanical bending of two common coaxial cables is obtained. When the temperature is in 0-10 ℃, the phase shift of the cable will suddenly increase. When the bending radius increases from 50 to 200 mm under static mechanical bending, the phase shift of the cable will be reduced by half. The influence of these factors should be taken into account when selecting coaxial cable and determining the application environment.