Provided is a method where mobile relay performs bidirectional inter-terminal communication in wireless communication system. The method includes determining optimal values of predetermined variables for maximizing a transmission ratio for the bidirectional inter-terminal communication during a predetermined time segment using pieces of basic information of at least one of the mobile relay, a first terminal, or a second terminal, transmitting setting information on the optimal values to at least one of the first terminal and the second terminal, and performing the bidirectional inter-terminal communication on the basis of the optimal values. The predetermined variables include at least one of a position of the mobile relay, a speed of the mobile relay, acceleration of the mobile relay, a downlink transmission power of the mobile relay, an uplink transmission power of the first terminal, an uplink transmission power of the second terminal, or a transmission resource allocation ratio for uplink and downlink.