A breathing apparatus includes a pressure regulating unit, a pressure detecting unit, a flow detecting unit and a processing unit. The pressure regulating unit has a coupling terminal. The pressure detecting unit is coupled to the coupling terminal and configured to detect an air pressure of the coupling terminal The flow detecting unit is coupled to the coupling terminal and configured to detect an air flow of the coupling terminal The processing unit is electrically coupled to the pressure regulating unit, the pressure detecting unit and the flow detecting unit. When the breathing apparatus is operated in a detecting mode, the processing unit is configured to configure the pressure regulating unit to modulate the air pressure to a detecting pressure within a detecting period according to a breath-in time parameter, a breathing frequency parameter and a pressure supporting parameter. An operation method of a breathing apparatus is also provided.
