In order to probe into harmful geological bodies such as faults, folds, seamthinning areas, collapse columns for the safety of coal mine production, the author designed and developed a highdensity resistivity instrument in accord with the requirements for coal mine explosionproof. Two independent channels, i.e., current channel and voltage channel, were designed. Each channel has two lowpass active filters and two notch frequency filters. Highresolution 24bit ADCs can improve antiinterference capability and measurement accuracy in the circuit. Furthermore, the instrument also has a portable intelligent distributed electrode system, which can flexibly compose a twodimensional measurement system. The instrument has been designed in accordance with the requirements for explosionproof in the coal mine.