In order to study the influence of partial etching gratings on the diffracted beam of waveguide gratings and improve the degree of freedom of integrated photonics design, the different structural properties of waveguide partially etched gratings at the edge or middle were analyzed by finite time domain difference method simulation. The input light wavelength is in the range of 1 400～1 700 nm, covering 1 550 nm communication wavelength. The simulation results show that the edge etching method has higher radiation efficiency, lower reflection efficiency, and can control the intensity distribution of the radiated light field. The reflected energy in the intermediate etch method waveguide is stronger and the linewidth is narrower. By using the two etching methods, the larger the grating size, the higher the radiation efficiency. When the grating size is fixed, the larger the waveguide width, the lower the radiation efficiency of edge etching. The partial etching method of waveguide gratings can be used to optimize the design of the integrated optical path.