This paper presents an overview of recent progress of radar for the image detection and characterization of targets. MIMO radar can improve on conventional target detection, parameter identification, and target classification performance via diversity of, among other things, its simultaneously transmitted waveforms. However, the mutual interference among the waveforms may lead to considerable performance degradation in suppressing clutter near targets. The performance of the conventional radar for moving target detection have been evaluated analytically mainly focusing on the Swerling model II, IV and V and their integration loss during the signal processing related with the threshold voltage level of matched filter . Finally this paper extended toward MIMO radar detection performance for moving target under the condition of unknown parameters or other fluctuating model.