The stress-inducing birefringence of the “pseudo-rectangle” polarization-maintaining optical fiber (PMF) was analyzed by finite element method, and its stress distributions curve and stress birefringence distributions were presented. This fiber's polarization modes, transmitting constants and modal birefringence were computed by the full vector finite element method. The stress and modal birefringence is about 3.33×10 -4 and 3.72×10 -4 in simulation conditions, respectively. The results of computation demonstrate that the “pseudo-rectangle” polarization-maintaining optical fiber has a number of obvious advantages with comparisons of the panda shaped fiber or the bow-tie shaped fiber: it is better in the stress transmitting effect, more uniform in the stress field distribution in fiber core and bigger in the stress-inducing birefringence.