The device is specially designed with clean water and emulsion livid of 5-60℃ and oil of viscosity no more than 45 mm²/s as the working media. The liquid is filled up quickly and pressure goes higher immediately when doing the testing initially. It is to reduce the testing time, has great flow volume. When the pressure is over 1.6Mpa (the pressure can be automatically adjusted lower), the flow volume is automatically reduced in order to keep the testing slow and stable. Thus the product has two flow volumes under high and low pressure, and it changes automatically. Any kind of pressure testing can be performed under the rated pressure output. Its working temperature is 5-60℃.