Abstract: Amodel DCM-1 digital observation system for geomagnetic pulsations has been developed for geomagnetic deep sounding and geomagnetic pulsation observation. The system consists of a fluxgate magnetometer with high sensitivity, data-acquisition subsystem, digital cassette and time service unit etc. The system features large dynamic range, low noise, high accuracy, low power consumption, and simplicity and convenience for operation. The system can be interfaced with a computer for data-processing, analog curves can be automatically plotted when the cassette is played back through the system. The system has been tested in the field and some valuable data have been obtained which contain much more information than by an analog recorder.