In Anzijiang dialect of Qiqihar Dagur (or Daur), they have two forms of reflexive possessive markers, -AA and -mAA, while other Mongolic languages in addition to any other Dagur dialects generally have only one form -AA or another cognate form. The distinction between -AA and -mAA depends on the usage of the reflexive possessive marker -ban/- ben and -iyan/-iyen) in written Mongolian. There are still some problems in this phenomenon, such as the reason why the form has remained only in Anzijiang dialect of Qiqihar Dagur, or why it hasn’t remained in the form of the instructive case marker. All this report depends on is only one consultant, so we have to investigate more and look for other dialects which also have same element -mAA. If it really has the element which the old Mongolian remains, this fact would contribute to historical studies of Mongolic languages.