A system access method of a narrowband terminal is provided for supporting both wideband and narrowband terminals in a cellular radio communication system. The method includes broadcasting a Shared CHannel (SCH) for a terminal to acquire system synchronization; transmitting a Low-end Master Information Block (L-MIB) including control information on an L-subframe configuration for supporting a second type terminal and a sub-band configuration of the L-subframe; transmitting a Low-end System Information Block (L-SIB) including information on downlink reception and uplink transmission of the second type terminal; and performing a random access procedure, when an attach request is received from one of the first type terminals and the second type terminals.