对于真空度的标识通常有两种方法，一是用对压力（即：较真空度）标识，二是用相对压力（即：相对真空度）标识。

There are usually two ways to mark vacuum degree, one is to use absolute pressure (absolute vacuum degree), and the other is to use relative pressure (that is, relative vacuum degree) to mark two.

所谓对压力是指，真空泵与检测容器相连，经过足够时间连续抽气后，容器内的压力不再继续下降而维持某一定值，这时容器内的气体压力值就是泵的对压力。如果容器内对没有气体，那么对压力就是零，这是理论真空状态。在实际情况中，真空泵的对压力值介于0～101.325kPa之间。对压力值需要用对压力仪表测量，在20℃、海拔高度＝0的地方，仪表的初始值为101.325kPa。

The so-called absolute pressure refers to the vacuum pump is connected with the detecting container, after sufficient time for continuous pumping, the pressure within the container will no longer continue to decline while maintaining a certain value, then the pressure in the container is absolute pressure pump. If there is absolutely no gas in the container, then the absolute pressure is zero, which is the theoretical vacuum. In actual situation, the absolute pressure value of vacuum pump is between 0 and 101.325kPa. Absolute pressure values need to be measured with absolute pressure gauges, where the initial value of the instrument is 101.325kPa at 20 and 0 altitude.

相对真空度是指被测对象的压力与测量地点大气压的差值。用普通真空表测量。在没有真空的状态下，表的初始值为0。当测量真空时，它的值介于0到－101.325kPa（一般用负数表示）之间。比如，测量值为－30kPa，则表示泵可以抽到比测量地点的大气压低30kPa的真空状态。同一台泵在不同的地点测量，其相对压力值可能是不同的，因为不同测量地点的大气压是不同的，这是各地的海拔高度、温度等不同客观条件造成的。

The relative vacuum refers to the difference between the pressure of the measured object and the atmospheric pressure at the measuring point.  Measuring with an ordinary vacuum gauge. In the absence of vacuum, the initial value of the table is 0. When measuring the vacuum, its values ranging from 0 to 101.325kPa (generally express with the negative number). For example, the measured value is 30kPa, said pump can be pumped into the vacuum measurement locations than the low atmospheric pressure 30kPa. The same pump is measured at different locations, and the relative pressure values may be different, because the atmospheric pressure at different measuring sites is different, which is caused by different objective conditions, such as altitude and temperature in different places.

国际真空行业通用的、也是比较科学的是用对压力标识；由于测量相对真空度的方法简便、测量仪器非产普遍、容易买到且价格便宜，因此它也得到广泛应用。当然，理论上二者是可以相互换算的。换算方法如下：对压力＝测量地点的气压－相对压力。

The vacuum industry general, is also the most scientific is the identity with the absolute pressure; the method for measuring relative vacuum degree measuring instrument is simple, non universal, easily available and cheap, so it has been widely used. Of course, in theory, the two can be converted into one another. The conversion method is as follows: absolute pressure = pressure relative pressure at the measuring site.