In this thesis, a design scheme for 3 mm T/R frequency conversion module in millimeter guidance hardware-in-the-loop simulation system was introduced.Those placed in module such as IF amplifier, sub-harmonic mixer, 3 mm low noise amplifier and automatic gain control (AGC) were mainly analyzed and researched.In this article, a feasible scheme of loading a circular polarizer in the front of the module to achieve anti-jamming and high-resolution was further put forward.According to radar seeker simulation test, the module is proved with fine amplitude and phase consistency, large dynamic scope, high signal-noise-ratio, good spectrum performance and other excellent characteristics in the millimeter guidance hardware-in-the-loop simulation system.