Objective Ultrafast lasers possess desirable advantages in the field of precision processing owing to their short pulse widths and highenergy peak densities. However, singlefocus ultrafast laser processing technology suffers from low processing efficiencies.Parallel processing by beam splitting using a spatial light modulator (SLM) is a solution for improving the efficiency of ultrafast laser precision processing. Improving the multibeam uniformity after beam splitting is a key issue in ultrafast laser parallel processing. Two factors deteriorate the quality of multiple beams: the approximations in beamsplitting algorithms, which leads to poor calculation accuracy, and the poor beam quality of the laser in optical paths. To address these issues, a feedback GS -GA algorithm based on realtime feedback is proposed in this study.Methods A spatial light modulator is used for phaseonly modulation by loading computergenerated holograms (CGHs). The algorithms for beam splitting and shaping are dominated by the Gerchberg -Saxton (GS) algorithm and its derivatives. The GS