The frame transmission method in the wireless local area network includes: generating, by an access point, a physical layer protocol data unit PPDU of a target type, where the PPDU includes a target media access control MAC frame structure that is generated in a target encapsulation format and that carries a trigger frame, and whether the target MAC frame structure includes a packet extension field is determined based on the target type and the target encapsulation format; and sending, by the access point, the PPDU.