Presently,a whole logic system is still absent to represent and reason various kinds of preferences.In this paper,a preference logic MPL(logic of many kinds of preference)is introduced to supply the gap.In addition, recurring to the minimal/maximal specificity principle,a non-monotonic semantics of MPL's language L_MPL is defined,and the application and capability of MPL are initially investigated by rewriting preferences expressed by ranked knowledge based into L_MPL.Moreover,the conclusion and the prospective are presented in the end.