A data communication method for a mobile communication system reduces the consumption of resources when a desirable half-duplex data connection is provided. The data communication method includes the steps of: a) determining whether data communication is needed between at least two MSs (Mobile Stations) located in a service area of one BTS (Base Transmit Subsystem); b) if the data communication between the MSs is needed, assigning one physical half-duplex data channel to the MSs in common; and c) if data is transmitted to the MSs over a downlink channel of the half-duplex data channel, adding a header to the data to create data, and transmitting the data to the MSs.