The present invention relates to network transmission technologies, and provide a Generic Framing Procedure (GFP)-based add/drop multiplexing (add/drop multiplexing) method, apparatus and system to improve add/drop multiplexing utilization, in which multiple Gigabyte Ethernet (GE) connections among multiple nodes are multiplexed in GFP to a byte synchronous interface for transmission, wherein a bandwidth of the byte synchronous interface is smaller than a sum of peak bandwidths of the group of GE connections borne on the byte synchronous interface; statistical multiplexing is carried out on effective data borne on the multiple GEs by means of buffers, and the effective data are treated by priority in the case of network congestion. The present invention implements statistical add/drop multiplexing for multiple data services in various types, and can be used in implementing a statistical ADM for diverse data services in burst mode, even a statistical ADM for multiple mixed services.