Instrument zero inspection and adjustment is a skill that instrument operator must master. This article introduces the method of checking and adjusting zero point of pressure transmitter, differential pressure transmitter, thermocouple display instrument and thermal resistance display instrument, It is of great help to the instrument operators for improving their technical level. When the operator has doubts about the indicator value of the instrument, it is necessary to check the instrument, the most commonly used method is to check whether the zero point of the instrument is correct. For pressure transmitter and differential pressure transmitter, check zero point after stopping process. The zero point of the instrument refers to the lower limit of the instrument’s measuring range (that is, the minimum value that the instrument can measure under its specific precision).