Disclosed are a multi-channel electrochemical machining device and method for a blisk, and relate to the technical field of blisk electrochemical machining. The multi-channel electrochemical machining device for a blisk comprises an electrolytic bath used for accommodating an electrolyte, a blisk workpiece, a tube electrode and a top cover plate. The top cover plate is located above the blisk workpiece. An electrolysis chamber used for the tube electrode to electrolyze the blisk workpiece is formed between the lower surface of the top cover plate and the surface of the blisk workpiece. The electrolysis chamber communicates with the electrolytic bath. A drainage seam communicating the electrolysis chamber and the electrolytic bath along the axial direction of the blisk workpiece is formed in the upper surface of the top cover plate.