The amplitude of the output voltage signal of ring resonator which consisted of right trapezoid prisms would be modulated in the mechanical vibration. From the perspective of engineering exploration, a new symmetry structure compacted with symmetry prisms to improve the ring resonator performance was put forward and discussed in the first time. The propagation property of the laser beam and the stress distribution in prisms of those two kinds of resonators was analyzed by theoretical computation and finite element analysis method. Results show that, as for the laser resonator that wavelength is 632.8 nm, the symmetry structure has a symmetry stress distribution, and the value is much lower than that in asymmetry one in prism by 15%. Compared with the asymmetry cavity′s output energy, the deviation extent of the symmetry one decreased more than 52.63% in one excitation period. From the results of simulation, using the symmetry resonator structure could reduce the stress induced birefringence in prism and off-axis range of the laser beam trajectory in the cavity, and improve the stability of output laser intensity and output signal quality effectively. The symmetry structure provides a new way for optimization design and reduction amplitude modulation for the ring resonator.