The invention discloses a sample acquiring method in a business identifying system based on DPI and DFI. The method comprises the following steps: a MainFrame module acquires message relevant information required by a DFI sample, three-layer information and four-layer information are included, and then each sub-module is invoked according to fixed logic; a ProtocolAly module carries out application protocol analysis according to fixed rules; an Auth module processes user authentication relevance and portal authentication; an StaUpload module counts class vector information required by the DFIsample and uploads the statistics information and (or) messages; an Nmfilter module realizes message control on FORWARD points; and a ProcessMsg module takes charge of user information configuration and final interaction of application-layer data.