A Ku band predistorter based on the analog predistortion technology is presented. Two Schottky diodes and three transmission lines are employed to generate pre-distortion signal. The adjustable amplitude and phase are realized by changing the bias voltage. At the same time, the slope of amplitude characteristic together with input Voltage Standing Wave Ratio(VSWR) is improved with the help of the balanced structure. It can be concluded from the simulation results that the predistorter can provide 17 dB gain expansion and 60° phase expansion at 14 GHz. In 12-16 GHz, it provides more than 15 dB gain expansion and 50° phase expansion, and the S11 is below -17 dB. The predistorter bears the advantages of wide band, simple structure and it is practical in use.