The present invention provides a communication method in a low power communication network, a corresponding low power communication network system and a network node, which enables low power consumption by the data transmission node in the low power communication network while ensuring the communication efficiency of the low power communication network. In this case, the network comprises a first network node and a second network node; the first network node transmits a beacon frame, said beacon frame is used to indicate the time for data transmission by the first network node; the second network node detects said beacon frame to synchronize its data transmission with the first network node. Furthermore, the first network node transmits a dummy beacon frame before it transmits the beacon frame, said dummy beacon frame is used to indicate the time for transmitting the beacon frame; the second network node detects the dummy beacon frame before it detects the beacon frame to acquire the time for transmitting the beacon frame, and carries out data transmission with the first network node synchronously after it has detected the beacon frame.