Deep underground observation is one of the future geoelectric observation methods for earthquake monitoring and prediction in China. This method is good for overcoming and reducing surface environment interference. In response to the demand of long-term stability of observation configuration in deep underground observation,this paper introduces a deep underground cable that involves the cable internal structure,making processes and preferred materials as well as the reliability test results. This type of cables can be used in geoelectric observation in deep underground. This cable can make sure the long-term stability of geoelectric observation configuration in deep underground,and also is a key technology to further continue the geoelectric observation in underground in China.