A ventilator, comprising: a first gas path, comprising a first pressurized gas source adaptor and a first flow adjustment device connected in sequence; a second gas path, comprising a second pressurized gas source adaptor and a second flow adjustment device connected in sequence; a third gas path, comprising a third pressurized gas source adaptor; a first inhalation branch configured for delivering inhalation gas to a patient; a switching device, capable of operating in comprising a first mixing mode where the first gas path and the second gas path are connected to the first inhalation branch, and a second mixing mode where the first gas path and the third gas path are connected; the second gas path further includes a pressure sensor that detects a gas pressure at the second pressurized gas source adaptor; a controller for controlling the switching device based on the measured value of the pressure sensor to enable the switching device to switch between the first mixing mode and the second mixing mode; and an exhalation branch configured for managing exhaled gas of the patient; characterised in that, the ventilator further comprises: a second inhalation branch configured for delivering inhalation gas to the patient, the second inhalation branch comprising a gas compression device and a first mixing cavity; when the switching device is controlled to operate in the second mixing mode, the switching device connects the first gas path and the third gas path to the second inhalation branch by the first mixing cavity, and the gas compression device is configured for pressurizing, during inhalation, a mixed gas that is mixed within the first mixing cavity. a first gas path, comprising a first pressurized gas source adaptor and a first flow adjustment device connected in sequence; a second gas path, comprising a second pressurized gas source adaptor and a second flow adjustment device connected in sequence; a third gas path, comprising a third pressurized gas source adaptor; a first inhalation branch configured for delivering inhalation gas to a patient; a switching device, capable of operating in comprising a first mixing mode where the first gas path and the second gas path are connected to the first inhalation branch, and a second mixing mode where the first gas path and the third gas path are connected; the second gas path further includes a pressure sensor that detects a gas pressure at the second pressurized gas source adaptor; a controller for controlling the switching device based on the measured value of the pressure sensor to enable the switching device to switch between the first mixing mode and the second mixing mode; and an exhalation branch configured for managing exhaled gas of the patient; characterised in that, the ventilator further comprises: a second inhalation branch configured for delivering inhalation gas to the patient, the second inhalation branch comprising a gas compression device and a first mixing cavity; when the switching device is controlled to operate in the second mixing mode, the switching device connects the first gas path and the third gas path to the second inhalation branch by the first mixing cavity, and the gas compression device is configured for pressurizing, during inhalation, a mixed gas that is mixed within the first mixing cavity. a second inhalation branch configured for delivering inhalation gas to the patient, the second inhalation branch comprising a gas compression device and a first mixing cavity; when the switching device is controlled to operate in the second mixing mode, the switching device connects the first gas path and the third gas path to the second inhalation branch by the first mixing cavity, and the gas compression device is configured for pressurizing, during inhalation, a mixed gas that is mixed within the first mixing cavity.