When using a high power amplifier(HPA) for high-speed communication, the nonlinear characteristics of the HPA cause power efficiency, bit error rate(BER) performance, and spectral efficiency to deteriorate. Since it is inevitable to use HPA to obtain sufficient transmission power for high-speed communication, it is necessary to compensate for nonlinearity of HPA by using a predistorter. In this paper, we analyze performance of multi-level modulation technique(M-ary) using HPA using Saleh nonlinear model in basic communication system based on M-QAM modulation with good power and spectral efficiency. In addition, a predistorter was used to compensate for the nonlinearity of the HPA, and the nonlinear distortion was compensated using HPA. As a result of the simulation, the output signal amplitude characteristics(AM-AM) and the output signal phase characteristics(AM-PM) with respect to the magnitude of the input signal are checked for the magnitude of the input signal, And the nonlinearity of HPA was compensated for. Also, by checking the BER performance, BER performance similar to that of the ideal linear amplifier can be obtained by using the predistorter.