The invention discloses a high voltage breaker filled air pressure temporary state quantity detection system and an application method thereof. The detection system comprises a high precision air pressure sensor, a high speed collection card, a trigger, and a power supply. The output terminal of the power supply is connected to the high speed collection card and the trigger. The high precision airpressure sensor is communicated with the inner cavity of a high voltage breaker. The output terminal of the high precision air pressure sensor is outputted through the high speed collection card. Thetrigger is connected and conducted with the fracture of the detected high voltage breaker. The application method comprises steps of detecting and diagnosing a high voltage breaker by using the detection system mentioned above. The data is collected in real time during the action process of a high voltage breaker, the inner state of the high voltage breaker can be represented effectively in realtime, the inner state of the high voltage breaker can be accurately judged, reference is provided for evaluating the performance of the breaker and making a maintenance plan, and the reliability of power supply is effectively improved.