A method and an apparatus for controlling a TX power amplifier are provided in the present invention. The invention is applied for generating a power control curve in a power variation area to control the power variation for signal transmission when the TX power amplifier transmits the data during two continuous time slots, which are a first time slot and a second time slot, respectively have a first transmission power value K1 and a second transmission power value K2. The invention is aimed at producing a concave inter-ramp control curve in a inter-ramp division of the power variation area for controlling the power variation of the TX power amplifier, where the power for signal transmission is transformed from the first transmission power value K1 to the second transmission power value K2.