Abstract: Ordovician limestone karst water hazard is the key threat to deep mining in north China type coal field. Complicated distribution of karst water is the main reason of the hazard. The transverse distribution of karst fissures in Xinwen coalfield was studied in detail by means of drilling, geophysical exploration, core X-ray diffraction and hydro-geological test. The results show that the transverse distribution of karst fissures is controlled by faults formed in tectonic movement and burial depth. Three indexesincluding fracture development index, Ordovician water temperature anomalies and drill water inflow were selected to quantitatively study the development degree of fissures, karst passage and water abundance in Ordovician, then predication model of karst water system in Ordovician was built based on genetic algorithm optimized support vector machine. The transverse distribution of Ordovician limestone runoff network is predicted; through the analysis of water level, the direction of seepage field of Ordovician limestone runoff network is determined. The results show that in the middle and deep part of the coalfield, the main runoff zone is roughly parallel to the distribution direction of the main structure NW-F10 fault zone, the deep strong runoff zone is mainly controlled by the main fault zone, and there are three runoff zones parallel to the NE fault zone in the shallow part, mainly because the fault fissure space is formed by the intense groundwater alteration in the shallow part.