Abstract: As wavelength division multiplexing/de-multiplexing devices, etching diffraction gratings (EDGs) are promising to be widely used in the optical communication systems. A new kind of EDG was designed and fabricated on silicon on insulator (SOI) platform with top silicon layer of 220 nm, which applied hexagonal-lattice air-hole photonic crystals as its reflection mirrors. Simulated results show that compared with the traditional EDGs based on stepped-grating reflection mirrors, the EDG based on photonic-crystal reflection mirrors could reduce the fabrication difficulty, decrease the insertion loss and realize the polarization maintenance theoretically. Afterwards, the EDG based on photonic-crystal reflection mirrors was fabricated with one step of deep ultraviolet lithography (DUVL) and one step of inductively coupled plasma (ICP) etching. The measured results show that the insertion loss of the device is 9.51-11.86 dB, and the crosstalk of it is 5.87-8.72 dB, which can be further improved by optimizing its fabrication process and optimizing the location of the output waveguides.