A ventilation treatment device and a ventilation-control method are provided. During use, when a headband contacts a headrest, a first valve assembly contacts a second valve assembly to open first air holes and second air holes, thereby communicating a first chamber with a second chamber, such that air from an air source into the first chamber enters the second chamber and further enters a respiratory chamber of a patient connecting apparatus for inhalation by a patient; and when the headband is separated from the headrest, the first valve assembly and the second value assembly are separated to close the first air holes and the second air holes, thereby preventing the air in the first chamber and the second chamber from flowing out through the first air holes and the second air holes, respectively.