In this paper, we proposed a method of evaluating the stress birefringence of fused silica in the deep ultraviolet waveband, in which the stress at several cross sections in the optical element was obtained by finite element simulation. Furthermore, the total phase retardation and azimuth introduced by the mechanical stress were calculated by three-dimensional interpolation fitting, Jones matrix, and path integration. Without considering the parallelism error of the element, the numerical results of phase retardance and azimuth at 632.8 nm were in good agreement with the experimental results, which verified the accuracy and effectiveness of the proposed method. On this basis, we derived the variation in the stress birefringence at 248 nm and 193 nm under the same loads, which can be used to analyze the effect of stress birefringence in optical elements on the polarization of optical systems.