Abstract: In general,the characteristic of the Radio Frequency Power Amplifier(RFPA) varies with many kinds of factors,such as the environment temperature,power supply,etc.In order to guarantee the steady operation of the predistortion RFPA,the adaptive performance of the predistortion system seems very important.This paper presents a new adaptive optimized algorithm applicable for predistortion RFPA.Its main ideal is to extract the out-of-band distortion of RFPA output and minimize it as the optimization goal,and use the multidirectional search algorithm which has stabilized convergence property to optimize the predistortion system,making the system operation in optimum state all the time.The simulation result indicates that the adaptive algorithm can achieves convergence more quickly than traditional adaptive algorithms and get improvement of 15dB for out-of-band distortion