A radio communication system for communication between a first mobile system and a second mobile system. Each mobile system has a transceiver for receiving and emitting radio signal. The second mobile system comprises a received signal strength detecting device, a power controller and an indicating device. The received signal strength detecting device detects a received signal strength of the transceiver in the second mobile system. The power controller outputs a transmitted power strength status and controls transmitted power of the transceiver according to the received signal strength. The indicating device receives the transmitted power strength status and indicates a transmitted RF power strength status of the transceiver in the second mobile.