Abstract: Analog predistortion is an effective way to compensate the amplitude and phase distortion generated by traveling wave tube amplifies(TWTA). However, low adjustment accuracy is a deadly disadvantage restricting its further development. Independently amplitude modulation to amplitude modulation (AM/ AM) and amplitude modulation to phase modulation (AM/ PM) control is an important technique to raise the accuracy of analog predistortion and so is shape control. A Ka-band predistortion linearizer with high adjustment accuracy is proposed in this paper. From 29GHz to 31GHz, The linearizer based on vector synthesis structure can realize both independently AM/ AM and AM/ PM control and shape control by adjusting the bias voltages of diodes. The test results show improvements in linearity are achieved. The AM/ AM and AM/ PM characteristics of TWTA are improved from 5.3 dB and 62° to 1.2 dB and 6.5° by the predistortion linearizer. The third order carrier-to-intermodulation (C/IM3) is improved 9.3 dB at -5 dB output back-off (OBO).