Method and system used for data management

The invention discloses a method and system used for data management. The method includes the steps that one or more of characteristic values including the characteristic value of first data of a first format and the characteristic values of one or more second-format data obtained by converting the first data, wherein the characteristic values solely represent arrangement characteristics of at least part of bits of the data of specific formats; the characteristic value, equal to the stored characteristic value corresponding to the second data, in the calculated one or more characteristic values is responded to, and one of the first data and the second data is stored. By means of the method and the system, duplicate removal can be conducted on data files from the same source data.