Abstract: This paper describes a new design method for adaptive feedforward power amplifier. The third loop is added to the conventional two loops feedforward system which could detect the intermodulation directly and there is no need for additional pilot signal any more. The DSP system is used to adaptively control three loops and makes the feedforward system automatically achieve optimum results. The achievement has been used in cdma2000 base station power amplifier. The ACPR of the amplifier is better than -50dB.