Provided are a method and device for controlling transmitting power. According to the method, when it is detected that a target object approaches a mobile terminal, a position, which the target object approaches, on the mobile terminal is determined, and an optimal sensing area for a Specific Absorption Rate (SAR) reducing antenna of the mobile terminal to sense a movement of the target object is selected according to the position; movement information of the target object is acquired by sensing the movement of the target object in the optimal sensing area by the SAR reducing antenna, and the transmitting power of the mobile terminal is controlled according to the movement information. The technical solution can improve the sensing distance and range of the SAR reducing antenna, namely, improve the sensitivity of the SAR reducing antenna.