Abstract: In view of the increasingly complex electromagnetic environment in the modern battlefield, radar signal sorting is facing severe challenges, put forward the hierarchical classification the environment signal PDW dataflow synthetically pretreatment method to dilute the dataflow then reduce the stress of the follow-up signal sorting, briefly introduced the presorting of radar signal processing flow based on the orientation of signal, the frequency and pulse width parameter, and explains several main points of the known signal preprocessing and the unknown signal preprocessing, the correctness and effectiveness is validated by computer simulation.