In order to reduce the volatility and heterogeneity of the cathode flow in numerical cont rol electrochemical milling， and improve the accuracy and surface quality of the wor kpiece in ele ctrolyti c machining， a spiral blade cathode structure is proposed. The flow model of the cathode structure is built and simulated by using the standard turbulence mode l. The simulation results show that the electrolyte flow velocity and pressure dis tribution are influenced by internal channels with different structures and diff erent technology parameters， therefore the structure of cathode is improved acco rding t o the simulation results. Finally， regarding the impeller as the milling object， experimen ts are carried out at the CNC composite electrolytic milling machining center. T he experimental results verify the validity and correctness of the simulation.