The present invention relates to a multi-mode communication system and a method thereof. The multi-mode communication system uses a first mode among a plurality communication modes for accessing a first mobility control entity (MCE) among a plurality of MCEs, and communicates data with the first MCE. The multi-mode communication system receives a paging request that has been transmitted from a multi-mode control entity (MMCE) for accessing a second MCE from the first MCE and analyzes the paging request, and puts the first mode into a sleep mode and a second mode for accessing the second MCE into an awake mode based on the analysis. Subsequently, multi-mode UE accesses the second MCE by using the second mode in the awake mode. According to the present invention, an MMCE for multi-mode control is provided to integrate and manage an idle state for each access mode of multi-mode user equipment, thereby minimizing power consumption due to access of the multi-mode UE to a radio access system. In addition, a change of the access of the multi-mode UE to the radio access system due to a paging request can be efficiently performed.