Abstract: Basedon the analysis of geoelectric field, observational system and the principle of measurement of the geoelectric field, this paper puts the focus on the key techniques of the observation system (including the Pb-PbCl₂ solid unpolarized electrode, ZD9A geoelectric field instrument, suchas principle of operation, specification, operation mode and system connection and others. The geoelectric field is an important geophysical field. Through analysis of various observed data, we can safely say that the data obtained by the observational network can reflect the earth surface's geoelectric field and its space-time variation. This will provide the technical support to the com prehensive observation and re search of the geoelectromagnetism.

Key words: Geoelectric field, Observational system, ZD9A geoelectric field instrument, Solid unpolarized electrode, Data processing