A communication management method for a mobile communication device is provided and includes the steps of connecting first and second wireless communication units respectively to first and second service networks according to first and second information respectively provided by first and second Subscriber Identity Modules (SIMs); using first wireless communication unit to establish first call connection with remote communication device and afterward comparing qualities of first and second signals respectively received from first and second service networks; when quality of second signal is superior to quality of first signal, using second wireless communication unit to dial first SIM to establish second call connection with first wireless communication unit and afterward automatically establishing first multi-call connection among first and second wireless communication units and remote communication device; and then automatically establishing third call connection between second wireless communication unit and remote communication device in place of first call connection.