In order to solve the problems of cathodic burn and low processing efficiency caused by dispersion,underfill and vortex in the electrolyte flow field between adjacent teeth of the rifling cathode,the working teeth with different size riblet surface were designed in terms of the theory of drag-reduction of riblet surface to optimize teeth shape and the gap flow field further.The gap flow field was simulated based on the COMSOL multiphysics.The influence of the shape parameter of riblet surface upon the velocity,turbulence parameter and shear rate were discussed.It is proved that the riblet surface size likes s=0.2 mm, h=0.05 mm of the working tooth not only can reduce the friction,but also can stabilize the gap flow field.The ridged biomimetic structure cathode was used to conduct relevant electrolytic machining experiments,and the slices of the breeched workpiece were measured and analyzed.The results show that the ridged biomimetic structure cathode meets the design requirements and the machining accuracy of the parts is guaranteed.