The present disclosure relates to data communication methods and apparatuses. The data communication One example method includes when receiving a physical layer protocol data unit (PPDU), obtaining, by a network node, a basic service set (BSS) identifier in the PPDU. If the BSS identifier in the PPDU is different from a first BSS identifier and same as a second BSS identifier, the network node determines whether the PPDU meets a preset spatial reuse condition, where the first BSS identifier is an identifier of a first BSS to which the network node belongs, the second BSS identifier is an identifier of an extended BSS to which a target relay belongs, and the target relay and the network node belong to the first BSS. If the PPDU meets the preset spatial reuse condition, the network node contends for an access channel, and communicates with a station other than the target relay in the first BSS.