Abstract: Investigation of the polarization characteristics of maritime radar echoes is the foundation of radar target recognition and interference suppression. Maritime radar echoes are composed of target echo and sea clutter. Thereinto, the target could be airplane, vessel, missile or unmanned aerial vehicle, and sea clutter is the key factor affecting radar detection performance. This paper summarizes the research status of cognition of polarization characteristics of sea clutter and the above mentioned target echoes. It also presents some main conclusions and future work.