Aiming at 1μm high resolution in imaging an inertial confinement fusion (ICF) target, a method is developed for analyzing the direct imaging by a Fresnel zone plate (FZP), and numerical calculations are carried out to study the FZP imaging characteristics in thekeV X-ray range. For the Ti K α line (photon energy 4.51keV, wavelength 0.275nm), the FZP parameters are suggested, for which the technical requirement of fabricating the outmost zone is relatively low. The influence of the target size on the imaging is studied for the first time. It is shown that the FZP has a large effective field of view and the image quality can be guaranteed even for a target of several millimeters. The influence of the spectral bandwidth of a polychromatic incident light on the imaging is also studied. Monochromatic imaging can be obtained due to the achromatic property of the FZP. However, if the bandwidth is larger than a certain limit, the image contrast will be degraded. These results indicate the feasibility of applying an FZP in high-resolution X-ray imaging of an ICF ignition target and put forward the requirements as well.