Deep well natural electric field observation is an effective means to monitor the geological activities in the deep earth, and is of great significance to the prevention of earthquake disasters and the exploration of deep resources. In general, the ground electric field signal is a weak electrical signal of the mV level or even the light V level. As a non-polarized electrode of the electric field sensor, its performance will have an important impact on the measurement results. The existing non-polarized electrode works mainly on the principle of electrochemistry, but in the deep well, the high temperature, the acid corrosion and other harsh conditions exist. According to electrochemical theory, factors such as high temperature and acid corrosion will severely impact the performance of non-polarizable electrode. In order to make high temperature and acidic environment inspection of wells of non-polarizable electrode and the suitability of the principle of electrochemical non-polarizable electrode to deep well measurement and the related experiment, the authors selected three kinds of electrodes and tested them under simulated conditions of deep well testing. The results show that the principle of electrochemical non-polarizable electrode electric field measurement is not suitable for deep well environment, graphite electrode performance is stable, and graphite substances are suitable electrode materials for deep wells.