Disclosed are multi-user transmission methods in a wireless local access network (WLAN). An operation method performed in a first station may comprise generating a physical layer convergence procedure (PLCP) protocol data unit (PPDU) including a legacy preamble, a high efficiency (HE) preamble, and a payload; and transmitting the PPDU. Also, the HE preamble may include a HE signal A (HE-SIG-A) field, a HE signal B (HE-SIG-B) field, a HE short training field (HE-STF), and a HE long training field (HE-LTF), and the HE-SIG-A field may include information indicating the number of symbols of the HE-SIG-B field. Accordingly, a performance of the WLAN may be enhanced.