The invention discloses a normal-pressure filling machine capable of preventing dripping and sucking back. Its structure includes a feeding hopper, a fixed seat, a fixed frame, a workbench, a filling head, and a connecting cavity. The feeding hopper is installed on the fixed seat. , the feeding hopper communicates with the connecting chamber, the bottom of the connecting chamber is equipped with a filling head, the filling head is set in the north direction of the workbench, the filling head is matched with the workbench, the fixing frame and the fixing seat are mechanically welded, and the fixing frame and the working table are mechanically welded. The table is fixedly connected, and the beneficial effect of the present invention is that by setting up a drainage block in the middle cavity, the liquid reaching the drainage block can be guided under the action of the guide plate and the guide block, so as to prevent the retention of the filling liquid. When rotating around the central axis, it drives the telescopic plate to move accordingly to realize the opening and closing control of the vent. With the help of the vent, when the filling is stopped, the air pressure balance between the middle cavity and the outside world can be achieved, thereby preventing the filling tube from leaking. The air pressure is less than the air pressure outside the tube, causing the liquid to flow back and suck back.