First of all, we should have a more comprehensive understanding of all aspects of the tested object. It mainly includes: the properties of the tested object, whether it is condensable gas or non condensable gas, whether it is single or mixed, inert gas or active gas or corrosive gas; Whether the air flow state is steady or instantaneous, whether it is uniform or non-uniform; Whether the temperature is isothermal or non isothermal, high temperature or low temperature; Whether there are special conditions such as magnetic field, electric field, vibration, impact, acceleration, charged particles, radiation, etc. Secondly, according to the situation of the tested object and the research purpose, correctly select the vacuum gauge, and need to understand the principle, range and limitations of the selected vacuum gauge, so as to use the vacuum gauge correctly. Third, we should understand the interaction between the vacuum gauge and the measured object. The principles of various vacuum gauges are different, and its introduction may cause changes in some states of the measured object; At the same time, the gas in the measured object may also affect the vacuum gauge, change its performance and interfere with its work. Moreover, when introducing the technical characteristics of vacuum measurement, fozhen has mentioned that the measurement accuracy of vacuum measurement is not high due to many influencing factors and difficult to control. Therefore, in order to carry out ideal vacuum measurement, we must fully understand the above-mentioned problems, so as not to cause greater errors or errors.