The invention provides a bidirectional service data flow identification method and device. The method includes the following steps: carrying out frame counting on service data flows and carrying out depth packet detection identification on the same frame of data; carrying out result arbitration on the identification result of the same frame of data; detecting whether frame data, the result of which is not identified, exist, and carrying out depth flow detection identification on the frame data, the result of which is not identified, so that the identification result of bidirectional service data flows is obtained, wherein the service data flows include an uplink service data flow and a downlink service data flow, and the identification processes of the uplink service data flow and the downlink service data flow are identical and the identification processes are carried out at the same time. Through depth packet detection identification of the frame data of the service data flows, and depth flow detection identification of encrypted services which cannot be identified, wherein the identification granularity is frame, and through comprehensive utilization of DPI and DFI identification technologies, the bidirectional service data flows are both identified so that the efficiency of service data flow identification is improved.