<p>A communication method in an automatic system is provided. The system includes an access point and more than one client; the client receives downlink data which is sent by the access point and sends uplink data to the access point; the data transmission is divided into a master multi-receiver aggregation stage and more than one slave multi-receiver aggregation stage; in the master multi-receiver aggregation stage, the access point aggregates the data which will be sent to the more than one client into a packet to be transferred in the downlink; in the slave multi-receiver aggregation stage, the access point aggregates the fault data in the transmission of the master multi-receiver aggregation stage into a packet to be transferred in the downlink. Applying the method of the present invention enables the access point to control the uplink and downlink data transmission strictly, the determinacy in the automatic communication process is enhanced, and the cycle time is shortened further.</p>
