Filtering in polarization domain has been investigated with respect to the unknown and time-varying clutter or interference environment.An adaptive recursive-filtering algorithm is proposed.At first

the polarization coherence matrix is estimated by the independent secondary data.Then the polarization of antenna is optimized according to the polarization information.At last

the minimum complex volume is obtained.The recursive scheme makes it go fluently.The simulation experiments demonstrate its validity.The performance curve of stability approaches the optimum theoretically.The study curve reflects its transition property.