A transmit output controlling circuit and method of a wireless mobile communication system comprises a demodulating portion for detecting an immediate frequency of a receive information induced through an antenna and passing through a duplexer portion; a receive sensitivity measuring portion for detecting a receive sensitivity level of the immediate frequency signal detected by the demodulating portion; a controller for receiving data from the demodulating portion and outputting a receive sensitivity data, a timing control signal and a transmit power control signal; a transmit signal control a receive sensitivity data into a transmit signal according to the receive sensitivity data and the timing control signal from the controller; a transmit output amplifying portion for amplifying the transmit signal from the transmit signal control; and a transmit power control for controlling an amplification factor of the transmit output amplifying portion according to the control signal from the controller, so that the transmit output level is controlled according to the receive sensitivity and the communication distance, thereby reducing the power consumption in a local communication.