Aiming at the problem that the sub-wavelength grating polarization b eam splitter can not realize vertical exiting light and can not get high integration coupling efficiency.Thi s paper designs a sub -wavelength grating polarization beam splitter with beam deflection ability .This optical device can separate the poliarized beam and get the vertical outgong light.The upper layer of the optical device is a periodic sub-wavelength grating polarization beam splitter which is designed w ith grating diffraction theory. The lower layer designs a nonperiodic sub-wavelength grating with beam deflect ion ability by rigorous coupled wave analysis and wavefront phase control theory.Based on the finite ele ment software COMSOL,we perform simulation analysis on the designed optical device.The simulation resul ts show that the optical device can separate mixed TE and TM polarized light into two types of single pol arized light,and each single polarized light can exit the port vertically.The total transmittance of the two polarized lights exceeds 76.5% at 1550nm,and the polarization extinction ratio is 14.0dB.T herefore,the polarizing beam splitter can not only obtain the single-polarized light that can exit the port vertically,but also improve the working efficiency of the vertically coupled device effectively,and is expected to be u sed in integrated optoelectronicdevices for fiber optical communication.