To obtain high-resolution electron bombarded complementary metal oxide semiconductor (EBCMOS) imaging devices, the influence of spatial resolution for EBCMOS proximity region is studied. The theoretical calculation model for spatial resolution in EBCMOS devices proximity region is established according to the principle of Fourier transform and electromagnetic fields. Effects of illumination, proximity distance, and proximity voltage on resolution are studied. The diffusion diameter of photoelectrons reaching the back-side bombarded CMOS (BSB-CMOS) surface can be reduced by reducing the proximity distance and increasing the proximity voltage, which will result in higher spatial frequency. The electron focusing and resolution will not varied when the magnitude of illumination is changed. When the proximity distance is 100 μm and proximity voltage is 3000 V, the electron beam diffusion diameter can be reduced to 10 μm, and the limit resolution can be increased to 127.27 lp/mm. This structure can effectively improve the resolution of the EBCMOS proximity region. Therefore, the research on the influence of spatial resolution in EBCMOS proximity region will provide a theoretical support for optimizing proximity structures and improving EBCMOS resolution.