Penetrating imaging radar technology uses the characteristics that the electromagnetic wave can penetrate the medium, to get high-resolution image of discontinuities in the non-metallic medium. In order to realize millimeter high plane resolution, high detection efficiency and high portability of the radar system, a high plane resolution penetration imaging radar system was designed. Continuous wave system and fast scanning spatial sampling scheme were adopted to ensure miniaturization and high imaging performance. An integrated radar RF front end was realized. Data processing methods such as autofocus imaging processing under the condition of unknown parameters were proposed. A prototype of penetrating imaging radar system, which weighs only 2.5 kg and can be operated by one person and one hand, was developed. The experimental tests of imaging resolution and penetration ability were carried out to verify the feasibility and effectiveness of the scheme.