Abstract: Microwave electromagnetic characteristics in radar measurements of burden surfaces and media thickness of an ore and coke (O/C) layer were researched in the closed environment of a blast furnace (BF). With electromagnetic calculations and CST simulation software, a dielectric constant model of the media layer was developed to study the transmission, reflection and absorption characteristics of the burden surface and the O/C layer in BF. Also a reconstruction relational model of the number of distributing O/C layers in BF, microwave angle and frequency band concerned with the dielectric constant of the media layer was established. Using trans-mission and reflection electromagnetic characteristics of radar waves, combining with BF radar distributed radar sensor array installation and the different dielectric constants of the O/C layer in BF, the three-dimensional reconstruction imaging of burden surfaces and O/C layer thickness in BF was realized on-line.