The holographic waveguide coupling element is a key optical component of the holographic waveguide imaging system. The beam is perpendicularly incident into the holographic waveguide plate and changes the beam propagation direction through the in-coupling element. A waveguide phenomenon is formed in the waveguide plate and transmitted to the out-coupling element. The direction of transmission is changed again from the holographic waveguide plate to the human eye through the coupling element. When both the in-coupling element and the out-coupling element are transmissive or reflective coupling elements, the angle values of changing the beam propagation direction twice are equal. Based on the imaging principle of holographic waveguide, combined with k-vector circle theory and holographic optical recording principle, a symmetric periodic structure of the holographic waveguide in-coupling element and the holographic waveguide out-coupling element is designed. The interference light intensity model of the holographic waveguide coupling element is simulated by MATLAB software. The change of the beam propagation angle caused by the coupling element of the holographic waveguide is simulated by using COMSOL software. The experimental results are consistent with the theoretical change of the beam propagation direction. It is proved that the two holographic waveguide coupling elements are arranged symmetrically in the holographic waveguide optical system, which can meet the requirements of the holographic waveguide optical system for the beam propagation direction.