Abstract: In order to meet the demand of high rate communication services in the spaceborne high rate data transmission system,the new digital modulation systems (such as OFDM, M-QAM, etc.) are increasingly used, but the resulting nonlinear effect of the power amplifier is also becoming more serious, which has a great impact on the performance of the demodulator. The traditional digital predistortion algorithm is not suitable for the spaceborne high rate data transmission system with strict resource limitation due to its slow convergence speed and higher computational complexity. In this study, a recursive least squares algorithm based on QR decomposition (QRD-RLS) was proposed. The theoretical analysis and performance simulation of the algorithm were carried out. Compared with the traditional predistortion algorithm, the algorithm has the advantages of small steady-state error, fast convergence speed and low computational complexity. Based on the algorithm, a high rate modulator structure with predistorter was designed. The test results of 16QAM signal show that the predistortion scheme based on QRD-RLS can provide a significant compensation effect on the distortion signal, and the error vector magnitude (EVM) can be reduced from 7.4% to 2.5%, the out of band interference suppression can be increased by 10 dB.