To attain the one-dimension high range resolution profile of a targe, a wide-band miniature millimeter-wave system is needed. In this paper, the miniature system design of a stepped-frequency millimeter-wave radar is presented. Firstly, the reasonable transmitted waveform is analyzed and selected. The simple system configuration is provided to obtain the high resolution range profile with the smallest volume, in the meanwhile, the method to increase the isolation of the transmitter and the receiver is presented and discussed. The experiment result is also given to proven the designed system performance. At last, a new system configuration is introduced. In this paper, there are some significant academic analyzing and engineering application about miniature MMW radar to be obtained.