A method and system for controlling the transmitting power of an antenna is provided, the system including a detecting device directly receiving signals from the antenna, the detecting device configured to obtain a voltage standing wave ratio of the antenna; and a control device coupled to the detecting unit. The control device includes a monitoring unit configured to calculate a real transmitting power value of the antenna based on the voltage standing wave ratio; a comparing configured to compare the real transmitting power value with an expected power value to generate an error value; and an adjusting unit configured to output a power adjusting signal for controlling the transmitting power of the antenna based on the error value.