In order to improve the display brightness and view uniformity of the vector light field， a metagrating structure for circularly polarized light field imaging was proposed. The effect of incident light polarization state， grating structure and incident angle on the diffraction efficiency of -1st order light were studied by simulating the structure of metagrating pixel by pixel using a rigorous coupled wave analysis method. The simulation results showed that the circularly polarized light display could make the diffraction efficiency of the grating stable and efficient. When the grating period was 500 nm， the diffraction efficiency of the grating structure based on the circular polarized light increased by 18.5% and 2.6% compared with TE and TM. The height and duty cycle of grating had a significant impact on the diffraction efficiency. Considering the difficulty of metagrating fabrication， diffraction efficiency and viewing angle uniformity， metagratings array structure with the height of 0.6 μm and duty cycle of 0.4 was designed for circular polarization. The diffraction efficiency of the system could reach more than 40%， and it had better comprehensive performance， which was a guideline for metagrating design and preparation， as well as naked-eye 3D display.