A high-performance and compact binary blazed subwavelength grating coupler was designed, which consists of the upper grating coupler and the lower layer grating reflector. A large part of light transmitted out to the substrate due to the existence of gratings can be efficiently reflected with normal incidence. Then, the propagating light is augmented and the coupling efficiency obtains its maximum value. By the appropriate choice of grating parameters, including thicknesses, periods, height, and filling factor, a coupling efficiency of beyond 80% at wavelengths from 1.535 to 1.555 μm is calculated. Finally, the device layout is simple, feasible, and compatible with standard complementary metal-oxide semiconductor technology processing.