This application describes a frame aggregation method. A first forwarding node device receives a first data frame and a second data frame, where the first data frame includes a first MAC header and a first MSDU, the second data frame includes a second MAC header and a second MSDU, and a destination MAC address in the first MAC header is the same as a destination MAC address in the second MAC header; and generates a first aggregated frame, where the first aggregated frame includes an aggregated MAC header and an aggregated MSDU, the aggregated MSDU includes a first sub-MSDU and a second sub-MSDU, the first sub-MSDU includes the first MSDU and a source MAC address of the first data frame, and the second sub-MSDU includes the second MSDU and a source MAC address of the second data frame. A second forwarding node device sends the first aggregated frame.