The invention relates to the technical field of turning, and discloses a blade drilling device for an electric fan. The blade drilling device comprises a frame, a cooling box, a worktable, a work chamber and a fixture box, a drilling device positioned on the upper portion of the worktable is arranged on the frame, the cooling box is communicated with a liquid outlet pipe, the drilling device is fixedly connected with a fixing block, the work chamber and the fixture box are positioned on the lower portion and the upper portion of the worktable, the upper surface of the work chamber is providedwith a collection opening, a first piston plate is vertically and slidably connected into the work chamber, a first connecting rod is fixedly connected between the first piston plate and the fixing block, a second piston plate is vertically and slidably connected into the fixture box, the side wall of the fixture box is fixedly connected with a heating device, a pressing block is vertically and slidably connected onto the frame, a second connecting rod is fixedly connected between the pressing block and the second piston plate, a second one-way liquid outlet valve is arranged on the side wallof the work chamber, and a cooling pipe is communicated between the second one-way liquid outlet valve and the cooling box. The blade drilling device is used for drilling fan blades, and cooling liquid can be timely supplemented.