A data communication method applied in a wireless local area network, comprising: constructing (S200, S300), by an access device, a beacon frame, wherein the beacon frame comprises a newly added field, and wherein the newly added field represents multiple data guard interval lengths supported by the access device, wherein the newly added field is placed in a "HE capability" element of the beacon field, wherein the newly added field includes an indicator bit of each data guard interval length, and the indicator bit is used to indicate whether the access device supports the preset data guard interval length or not; encapsulating (S201, S301), by the access device, the beacon frame into a first protocol data unit "PPDU1" complying with a protocol data unit structure in a first standard and encapsulating the beacon frame into a second protocol data unit "PPDU2" complying with a protocol data unit structure in a second standard; wherein, the first protocol data unit includes a preamble and first bearer data including the beacon frame; and a guard interval length of the preamble and a guard interval length of the first bearer data is a first alternative guard interval length supported by the access device in the first standard; wherein, the second protocol data unit includes a legacy preamble, a high efficiency wireless local area network preamble, and second bearer data including the beacon frame; and a guard interval length of the legacy preamble is the first alternative guard interval length supported by the access device in the first standard, and a guard interval length of the second bearer data is a second alternative guard interval length supported by the access device in the second standard; and broadcasting (S202, S303, S304), by the access device, the beacon frame encapsulated into the first protocol data unit and the beacon frame encapsulated into the second protocol data unit. constructing (S200, S300), by an access device, a beacon frame, wherein the beacon frame comprises a newly added field, and wherein the newly added field represents multiple data guard interval lengths supported by the access device, wherein the newly added field is placed in a "HE capability" element of the beacon field, wherein the newly added field includes an indicator bit of each data guard interval length, and the indicator bit is used to indicate whether the access device supports the preset data guard interval length or not; encapsulating (S201, S301), by the access device, the beacon frame into a first protocol data unit "PPDU1" complying with a protocol data unit structure in a first standard and encapsulating the beacon frame into a second protocol data unit "PPDU2" complying with a protocol data unit structure in a second standard; wherein, the first protocol data unit includes a preamble and first bearer data including the beacon frame; and a guard interval length of the preamble and a guard interval length of the first bearer data is a first alternative guard interval length supported by the access device in the first standard; wherein, the second protocol data unit includes a legacy preamble, a high efficiency wireless local area network preamble, and second bearer data including the beacon frame; and a guard interval length of the legacy preamble is the first alternative guard interval length supported by the access device in the first standard, and a guard interval length of the second bearer data is a second alternative guard interval length supported by the access device in the second standard; and broadcasting (S202, S303, S304), by the access device, the beacon frame encapsulated into the first protocol data unit and the beacon frame encapsulated into the second protocol data unit.