We present the design and fabrication of a novel dual-function high contrast gratings that can be used as a polarization-selective beam splitter with transverse magnetic polarization,which performs two independent functions,i.e.,reflection focusing and power equalization at a wavelength of 1550 nm.This dual-function grating profile is optimized by the rigorous coupled-wave analysis and the finite-element method.Simple analytical expressions of phase and modal guideline for the beam splitter design are given.The beam splitter based on the grating structure is experimentally studied at a distance of 160 pm from the reflection plane,the results are consistent with the theoretical results basically.