The present invention discloses a method for spreading a deep packet inspection result. The method includes: receiving, by an identification function network element, a data packet in IP network traffic; identifying the data packet; if the identification succeeds, save a first identification result obtained through identification in a local flow table of the identification function network element, and insert the first identification result in an extension field of the header of the data packet; if the identification fails, insert a second identification result in the header extension field of the data packet; send the data packet carrying the first identification result or the second identification result to a first downstream device. By means of the present invention, DPI service identification does not need to be performed on all network elements, thereby reducing a delay in executing a DPI service in an entire network and lowering a maintenance cost.