Abstract: Replacing standard mercury thermometers with high-precision digital thermometers based on industrial platinum resistors is a research hotspot in the field of thermometry.However,so far,such products can only be used as working instruments,the main reason is that the long-term stability of high-precision digital thermometers has not been studied sufficiently.The results of an eight year study on the stability of a high precision digital thermometer is introduced, and compares it with the standard mercury thermometer,shows that it is completely feasible to replace the standard mercury thermometer with a high-precision digital thermometer,and puts forward some specific suggestions.

Key words: Digital thermometer, High precision, Stability, Standard mercury thermometer, Temperature standard