Based on D. C. exploration data obtained in the principal inclined shaft of the Songlou coal mine and geological and hydrogeological conditions of the coal well, the author holds that the cause of water bursting in the principal inclined shaft should be underground karst water derived from Quaternary sandy gravel water-bearing horizon and deep horizons. Through electric exploration, the fissure-developed zone, water-rich area and water gushing position were located. After performing mud grouting water exclusion measures at these places, the production was resumed.