Echelle gratings with 90° apex angle have been successfully fabricated on 14° off-cut (110) silicon wafer by combining silicon anisotropic etch technique with inclined photolithography. The diffraction efficiency of blazed orders is measured in a wavelength region of 1500~1600 nm. The measurement results agree with theoretical results based on the C method. The grating has a strong blazing effect at wavelengths from 1500 nm to 1550 nm. The measured diffraction efficiency is about 52%~75% of theoretical value, thereinto, the peak efficiency is about 58%. At last, we discuss and calculate the diffraction efficiency of grating blazed orders caused by groove depth error in the production process. The results show that theoretical diffraction efficiency of blazed orders in consideration of groove depth error is about 77%~85% of perfect groove efficiency at wavelengths from 1500 nm to 1550 nm.