Multi-stage multi-time pitting method for middle high voltage anode foil

The invention discloses a multi-stage multi-time pitting method for a middle high voltage anode foil. The method comprises steps that pre-treatment on an aluminum foil is carried out; 1), the aluminum foil is placed in an electrolytic etching liquid containing sulfuric acid and chloride ions, and a DC current is applied to the aluminum foil to carry out primary electrolytic etching pitting; 2), the aluminum foil after electrolytic etching pitting is placed in a chemical etching liquid containing sulfur acid and chloride ions, primary chemical etching of the aluminum foil is carried out; and 3), the step 1) and the step 2) are cycled. Compared with a primary pitting method in the prior art, the DC current is applied to the aluminum foil to carry out electrolytic etching pitting for multiple times, after each electrolytic etching pitting, chemical etching is carried out, so the aluminum foil is made to realize a uniform and proper density pitting state, and the method is easy to realize and control.