The post-processed technique is a basic method for analyzing X-ray imaging. With the solution of radiation transfer equation of local thermal equation in stationary state and ray tracing method, a post-processed program for X-ray imaging was accomplished. It could reproduce X-ray imaging in ICF implosion. Numerical results of size of compressed core and duration of doped argon and coated sulfur spectrum are coincident with the data of implosion experiments in Shenguang-Ⅱ.