DDC-2 electronic automatic compensater is still being used in hydrogeolo-gical and engineering geological work. Nevertheless, this instrument is pondero-us and has low observation precision and little Tesistance to interference. The DWD-1 type microcomputer electrical sounding instrument designed and produ-ced by Beijing Geological Instruments Factory has attained the advanced levelin China. Its working principle, properties and test result in the field are descri-bed in this paper.