A design theory was demonstrated to design diffraction optical waveguides in wave-vector space. Systematic simulations were performed to investigate relationships among wavelength, grating period, clocking angle, waveguide substrate refractive index, dispersion to field of view and related parameters. Simulation results showed that light sources with broad bandwidth showed little effect on the design results because of the acceptable result of the edge wavelength FOV cutting. The dispersion of waveguide substrate showed negligible effect on diffraction optical waveguides. It is easy to manufacture to choose 40-270-140 clock-angle in design because of the suitable dimensions and positions of grating areas. The results in this work provide positive guides to design diffraction optical waveguides.